(CNN) It's a question every mom and dad wants answered: What are their kids really up to?
Today, parents are getting some insight from the Centers for Disease Control and Prevention's Youth Risk Behavior Survey, which has been conducted every other year since 1991. It now covers 118 health behaviors, as well as statistics on obesity and asthma.
The report notes that the prevalence of most health-risk behaviors -- such as riding with a driver who had been drinking alcohol, physical fighting and current cigarette use -- has decreased. Some behaviors and outcomes have not changed, including suicide attempts treated by a doctor or nurse, smokeless tobacco use, having ever used marijuana and attending physical education classes. Some have increased, such as being obese or overweight and not drinking milk.
The survey "helps us identify newly emerging behaviors and monitor long-standing youth risk behaviors over time," said Laura Kann (PDF), chief of the CDC's School-Based Surveillance branch. "While overall trends for the 2015 report are positive, the results highlight the continued need for improvements in reducing risks among teens."
The 2015 survey includes results from a national survey, 37 state surveys and 19 large urban school district surveys, conducted among students in grades nine through 12. In all, more than 15,000 students took part in the survey. Participation was voluntary, and responses were kept anonymous.
Here are the highlights from each of the report's six categories, as well as some insight from CNN's extensive reporting on all of these areas of health and wellness.
Motor vehicle crashes are the leading cause of death for people ages 10 to 24, accounting for 23% of deaths in that age group, according to the CDC.
"Nationwide, 42% of students who had driven a car or other vehicle during the past 30 days reported texting or emailing while driving," according to the report. "This percentage did not change from 2013."
Every day, more than eight people are killed and more than 1,100 are injured in crashes that are reported to involve a distracted driver, according to the CDC. In addition to texting or emailing while driving, the agency warns about activities such as talking on a cell phone, eating or using a navigation system.
Currently, 46 states, plus Washington, Puerto Rico, Guam and the U.S. Virgin Islands, ban texting while driving for drivers of all ages, according to the Governors Highway Safety Association.
"When you're texting and driving, your reaction time decreases, your concentration decreases," said CNN Chief Medical Correspondent Dr. Sanjay Gupta. "People have likened it to driving with a blood-alcohol level of .08. Just like they say, you don't let friends drive drunk; you don't let friends drive while texting, either."
New technology allows drivers to utilize auto-replies if someone tries to text or call while you're behind the wheel. Other apps can monitor your speed (via your phone's accelerometer) and disable your phone if it detects you're moving too fast.
"Your best bet, which is something I've started doing as well, is just put the phone out of reach," Gupta said. "However long it takes you to get home, most of those calls, those emails, those texts -- they can wait."
The report offers good news about where things stand now but is wary about the future.
"Current cigarette smoking is at an all-time low, which is great news," CDC Director Dr. Tom Frieden said. "However, it's troubling to see that students are engaging in new risk behaviors, such as using e-cigarettes."
Current cigarette use has decreased significantly, from 28% in 1991 to 11% in 2015, according to the report. But 24% of high school students reported using e-cigarettes in the past 30 days. This is the first time the survey has measured e-cigarette use.
In May, the Food and Drug Administration finalized a rule that allows the agency to regulate e-cigarettes, cigars and hookahs in the same manner it regulates traditional cigarettes.
From a health perspective, teenagers -- especially between ages 15 and 17 -- are most vulnerable to addiction, at a time when their brains are still developing, according to a report released last year by the Institute of Medicine (PDF).
"Tobacco (is) arguably the most addictive substance on the planet, which has no redeeming qualities whatsoever, in any way, shape or form," Gupta said. "No matter what your age, smoking is one of the single worst things you can do to your body."
Some studies have shown that e-cigarettes can be an effective aid in smoking cessation. Other research, which has focused on teens, found that those who used e-cigarettes were more than three times as likely to smoke traditional cigarettes.
"We must continue to invest in programs that help reduce all forms of tobacco use, including e-cigarettes, among youth," Frieden said.
"Nationwide, 17% of students had taken prescription drugs (e.g., Oxycontin, Percocet, Vicodin, codeine, Adderall, Ritalin or Xanax) without a doctor's prescription one or more times during their life," the report said.
Taking a prescription that hasn't been written for you by your doctor for an explicit purpose is almost never a good idea. What's more, in many places, it's illegal to share pills that have been prescribed to you with someone else. Without consulting your doctor, there's also no way of knowing what reaction you will have or what kind of interaction could occur because of another drug you might be taking or a pre-existing condition you may have.
The biggest potential problem, though, is "stacking." It's when someone combines one medication with another prescription drug, an illegal drug or alcohol. It can amplify the effects of one or both substances and can put your health at great risk.
The percentage of high school students who are currently sexually active -- meaning they had sex during the past three months -- has been decreasing since 1991, according to the report. It dropped from 38% in 1991 to 30% in 2015.
But, "among high school students who are currently sexually active, condom use decreased from 63% in 2003 to 57% in 2015."
Because of either misinformation or a lack of information, many teens are under the impression that sex while using birth control is safe sex. The bottom line: There is no pill that protects against sexually transmitted infections, with one notable exception. A medication called PrEP has been shown to be almost as effective as condoms in preventing sexual HIV transmission. Currently, the pill (brand name Truvada) is recommended by the CDC only for those at high risk of contracting the virus.
Nationwide, just 10% of students had ever been tested for HIV, according to the report. Some high school students may be worried about getting tested because they're afraid their parents will find out through their health insurer.
One simple solution for families would be to make getting tested a yearly occurrence, at a minimum, in an effort to remove some of the stigma. If the tests comes back negative, you've put your mind at ease. If you do test positive, the sooner you go on medication, the better -- and you won't pass the virus on to someone else.
The obesity epidemic in this country is getting worse. But there was a glimmer of hope in today's report, which found a significant decrease in young people drinking soda one or more times a day. It was down from 27% in 2013 to 20% in 2015.
Calories consumed from sugar-sweetened beverages are far worse for you than calories consumed from food, even the fatty fast-food variety. That's because without the fiber -- say, in the skin of an apple -- the sugar hits your liver all at once in a sort of "sugar tsunami." What's more, added sugars, like the kind found in sugar-sweetened beverages, are far worse for you than naturally occurring ones in fruit and dairy products.
Diet soda isn't much better. Some interesting research has shown that people who drink diet soda may consumer fewer calories overall, but a higher percentage of their calories came from "discretionary foods," such as cookies, chips, French fries and ice cream. The authors of that study say people who drink diet soda may feel justified to eat worse foods because they're "saving" calories when it comes to their drinks, or they may drink diet because they feel guilty about eating unhealthy foods.
If you're looking for a caffeine kick, switch to coffee or tea. If it's the fizz you're looking for, try seltzer with a squeeze of lemon or lime.
"Sedentary behaviors are still problematic," said Dr. Stephanie Zaza (PDF), director of the CDC's division of Adolescent and School Health. "Although TV watching for more than three hours a day decreased from 43% in 1999 to 25% in 2015, this behavior has been completely replaced by the use of computers."
"From 2003-2015, the percentage of high school students playing video or computer games or using a computer three or more hours per day (for non-school related work) nearly doubled, from 22% to 42%," according to the report.
There is an upside to that. Even the most simple games are more active (at least mentally) than passively watching television. The downside? Nearly every parent would agree that when they were a kid, this time was spent outside, doing something active.
The good news is that this might just be one of the simplest problems to fix: Put down the phone and get outside.