In the United States, teen-aged moms are increasingly rare. In 2016, the teen birth rate dropped 9% compared to the previous year, a new government report published Friday found. This record low for teens having babies continues a long-term trend.

The birth rate among teen girls has dropped 67% since 1991, according to the National Center for Health Statistics, which presented preliminary data for 2016 based on a majority (99.9%) of births.

In 2016, the number of US births totaled 3,941,109, a decline of 1% compared to 2015. The fertility rate of 62 births per 1,000 women is a record low for the nation.

The teen rate is a "phenomenal decline," said Dr. Elise Berlan, a physician in the section of adolescent medicine at Nationwide Children's Hospital. Berlan, who did not conduct this research, said the reason she's so excited is "because we know that the vast majority of teen births are unintended."

What's fueling the declines?

"Data [from previous years] really suggests it is access to contraceptives and use of contraceptives that has really led to these kind of changes," said Berlan, who noted that "most teens are using some form of birth control" and the top method is "the condom, followed by withdrawal and the pill."

Older moms

On the flip side, the increase in births to older moms is also important, said Martin.

For women between the ages of 30 and 34, the birth rate increased by 1% over 2015 -- the highest rate for this age group since 1964. The birth rate for women who are between 35 and 39 is up 2% over 2015, representing the highest rate since 1962.

Even older women, those between the ages of 40 and 44, showed a swelling increase of 4% over 2015 -- the highest rate for this group since 1966, according to the statisticians, while the rate of birth for women who are older than 45 is also a record high though the number of births remains essentially unchanged compared to last year.

Joyce A. Martin, a co-author of the report and lead statistician, also noted the declining rate of nonmarital births -- births to people who aren't legally married -- in 2016, which fell 3% compared to the previous year.

The report, first in a new annual series, provided additional vital statistics.