Every two years since 1991, the Centers for Disease Control and Prevention has released the results of its Youth Risk Behavior Surveillance System (YRBSS), which asks high school students across the country about a wide range of behaviors. Students note whether they wear bike helmets and seat belts, if they have ever texted while driving, whether they have experienced violence at school or in a dating relationship, whether they eat the daily recommended amount of fruits and vegetables, and if they have ever used alcohol, marijuana, or cocaine.

Of course, what often gets the most attention are the dozen or so questions about sex. Students are asked if they have ever had sex, if they have had sex in the last three months, if they started having sex before age 13, if they have had more than four sexual partners, and if they used alcohol the last time they had sex. They are then asked a series of questions about condoms and other birth control methods.

The questions about sex are pretty limited, but they provide a good snapshot of what the average high school student is doing at given points in time. More importantly, because many of the same questions have been asked in the exact same way for over two decades, the survey gives us a very good measure of how the behavior of today’s teens stack up against their predecessors and whether as a society we are making progress in helping teens adopt safer sexual practices.

The answer from the most recent survey, which was released on Friday, shows that on almost every measure, there was progress between 1991 and the 2000s, but that progress has either stagnated or, in cases like condom use, reversed.

On the issue of whether teens have ever been sexually active, the percentage decreased significantly between 1991 (54.1 percent) and 2001 (45.6 percent), but not much has changed in the years since then. The same stagnation can be seen in the number of students who had sex with four or more partners; it decreased from 18.7 percent in 1991 to 14.4 percent in 2003 and has not changed much since. Students reporting sex before the age of 13 dropped quickly between 1991 (10.2 percent) and 1997 (7.2 percent), but has been decreasing more slowly since then. And, finally, the number of high school students who are currently sexually active—defined as having had sex in the three months before the survey—declined only from 37.5 percent in 1991 to 34 percent in 2013. There was no statistically significant change for any of these measures between the last survey in 2011 and this most recent one.

But how many students are having sex is of less of a concern than how many students are having unprotected sex, which means we have to look at what the survey found regarding condom and contraception use. Again, on most measures we have either stopped making progress or have actually lost ground.

The decline of condom use may be the most disturbing, as condoms are often young people’s first method of contraception and remain the only method that protects against both unintended pregnancy and sexually transmitted infections (STIs). From 1991 to 2003, there was significant progress made in the percentage of sexually active students who reported using condoms the last time they had sex—it rose from 46.2 percent to 63 percent. Since then, however, condom use is becoming less common, with only 59.1 percent of sexually active high school students reporting using one the last time they had sex, in 2013.

Rates for other birth control methods have steadily increased over the last 20 years, and there are many more methods available to teens now than there were in 1991. Birth control pills remain the most popular, with 19 percent of sexually active high school students reporting that they or their partner used the pill to prevent pregnancy before last intercourse, in 2013. This number has actually steadily increased since 1995, when pill use was reported by 17.4 percent of sexually active high school students. In addition to the pill, 1.6 percent of sexually active high school students reported using an intrauterine device (IUD) or implant, and 4.7 percent said they used either the birth control patch, shot, or ring.

Still, the increase in these other methods does not mean we should stop worrying about the decrease in condom use. For one thing, none of these methods provides any protection against STIs. But also, the percentage of sexually active high school students who used no method at last intercourse is too high and doesn’t appear to be changing. Like other indications of safer sex, we saw progress here for a while and then stagnation. Specifically, the number of sexually active students using no method decreased from 16.5 percent in 1991 to 12.2 percent in 2007 but has not changed significantly since then. In 2013, 13.7 percent of sexually active students said they used no method the last time they had sexual intercourse.

Monica Rodriguez, president and CEO of the Sexuality Information and Education Council of the United States (SIECUS), told Rewire that even though progress has stalled, we have to remember that many of today’s teens are making responsible decisions. “It’s disappointing that we didn’t see increases in some of the protective data, but let’s give credit to young people for holding steady on many of the measures,” Rodriguez said, noting that if we want things to get better, it’s up to the adults. “All that the data indicate[s] is that we need to not only sustain our investment in adolescent sexual health education and services but, if we want to see improvements, we need to invest more.”

Debra Hauser, president of Advocates for Youth, agreed. She told Rewire, “Recent CDC findings report that 80 percent of teens between 15 and 17 have had no formal sex education before they have sex for the first time. So, it’s often too little too late. Plus, many of the schools that do provide sex education leave out vital lesson plans regarding condoms and very few adequately address the critical issue of healthy relationships. It’s not surprising that condom use has leveled off and the teen STD rates continue to be high.”

She added that to make progress, “society needs to recognize that adolescent sexual development is healthy and normal and empower young people with all of the knowledge and skills they need to mature into sexually healthy adults.”

“Communities—parents and schools—have a responsibility to provide young people with all of the information they need to make informed and responsible decisions about sex,” said Hauser. “And, we must redouble our efforts regarding condom education.”