In its overview of STDs in 2016, the CDC reports that each year in the US, there are about 20,000,000 new STDs. Half of those affected are young â between 15 to 24 years old. And at any given time, there are 110,000,000 new and existing sexually transmitted infections  In the slides above you'll find a snapshot of data for chlamydia, gonorrhea, and syphilis-the 3 notifiable diseases for which there are federally funded control programs.
References:
2016 Sexually Transmitted Diseases Surveillance. Centers for Disease Control and Prevention. Accessed October 3, 2017. https://www.cdc.gov/std/stats16/natoverview.htm