The age at which U.S. teens are starting to try alcohol, tobacco and some drugs is rising, according to new research.

Between 2004 and 2017, the average age at which teens started drinking alcohol and smoking increased from 16 to 17. For heroin, the average age increased from 17 to 18, and for cocaine it rose from 18 to 19. No increase was seen in the average age of first use for opioids or crack cocaine, HealthDay reports.

“These findings are certainly encouraging and also consistent with other recent research that has found reason to be hopeful that trends generally are moving in a more healthy direction for teens when it comes to tobacco, alcohol and other drug use,” said Linda Richter, Director of Policy Research and Analysis at the Center on Addiction, who was not involved in the study. She noted vaping of nicotine and THC, which has increased dramatically in recent years, has been an exception to this trend.