ST. PAUL (AP) -- A University of Minnesota report shows pregnancies and birth rates dipped to historic lows among Minnesota teens while sexually-transmitted diseases continue climbing.

The 2018 Minnesota Adolescent Sexual Health Report found a more than 70 percent decrease in the pregnancy rate of 15-to-19-year-olds and a 65 percent drop in births from 1990 - 2016.

Researchers say the decline is likely caused by delayed sexual activity and an increase in highly effective contraception.

The report says people age 15 to 19 accounted for 25 percent of chlamydia cases and 18 percent of gonorrhea cases last year, though that age range only accounts for about 7 percent of the state's population.

Report author Jill Farris says teens of color have higher rates of STDs and births.