A new report out of the Centers for Disease Control and Prevention has just come to an incredible conclusion about pregnancy in the United States. The report found that the teen birth rate has plunged about 9 percent compared to the previous year, a massive decline that sets a record low for teens having babies — and it looks like it’s part of a nationwide trend.

Overall, the birth rate for teen girls has dived 67 percent since 1991, according to the National Center for Health Statistics. A total of 3,941,109 births were recorded in the United States in 2016, which is a slight decline of 1 percent compared to 2015. The fertility rate is 62 births per 1,000 women, which is a record low for the country.

The findings came as a surprise to scientists, who came up with a few theories for why the teen birth rates were plummeting. Better access to contraceptives as well as education on how to use them were at the top of the list of those theories.

“15–19 declined 9% in 2016 to 20.3 births per 1,000 women; rates declined for both younger (aged 15–17) and older (aged 18–19) teenagers,” the CDC statement reads. “The birth rate declined for women in their early 20s to 73.7 births per 1,000 women aged 20–24 in 2016, and for women in their late 20s to 101.9 births per 1,000 women aged 25–29. The rates for women in their 30s and 40s rose in 2016.

“The nonmarital birth rate declined 3% in 2016, to 42.2 births per 1,000 unmarried women aged 15–44. In 2016, 77.2% of women began prenatal care in the first trimester; 6.2% had late (beginning in the third trimester) or no prenatal care. The cesarean delivery rate declined for the fourth year in a row to 31.9%; the low-risk cesarean delivery rate declined again to 25.7% in 2016. The preterm birth rate rose for the second year in a row, to 9.84% in 2016. The low birthweight rate was also up for the second straight year to 8.16%.”