The United States teen birth rate has dropped 57 percent over the past 20 years.

A government report revealed an estimated four million fewer births among teenagers, and is saving U.S. citizens a handful of tax money, HealthDay reported.

"We know, for instance, that only about 40 percent of teen mothers ever graduate from high school," Bill Albert, chief program officer of The National Campaign to Prevent Teen and Unplanned Pregnancy, told HealthDay. "Translate that number - [four] million fewer births -- into a much, much lower high school graduation rate, and think about the prospects for those young women in this day and age and in this economy. It's pretty sobering."

The decline in teen birth rates was observed across all 50 states and ethnic groups. The birth rate in this age group is only one-third of what it was when it reached a record high in the year 1957. In this year 96.3 of every 1,000 teen girls had a baby; by 2013 that rate had dropped to 26.6 out of every 1,000.

"In the old era, most teens who had a baby were married and you could support a family on the education you had from high school, so it was not as much of a concern," report author Stephanie Ventura, a senior demographer for the CDC's National Center for Health Statistics told HealthDay.

A steep increase in teen birth rates between 1986 and 1991 was thought to be a higher cause for concern.

"These historic declines in teen pregnancy and births truly represent one of the nation's great success stories over the past two decades," Albert said.

The researchers believe the drop is thanks to "more contraception and less sex" in teenagers. Teenagers have better access to contraceptives; better sex educations mixed with more concern about contracting infections such as HIV has made teens less likely to have sex.

Albert also suggested shows such as "Teen Mom" and "16 and Pregnant" have opened teens' eyes to the reality of having a child.

"Many teens have described these shows as far more sobering than salacious, and they are watched by millions," he HealthDay reported.