Fertility levels have a direct impact on the size and composition of the United States population. Now, according to a new report from the National Center for Health Statistics (NCHS), the current total fertility rate in the United States is at a level below that which is needed for a population to replace itself, CNN announces.

Researchers closely examined data for each state and total fertility rates (TFR) based on information from birth certificates for 2017. (TFR are estimations of the number of births that a hypothetical group of 1,000 women would have over their lifetime, based on birth rates by age in a given year.)

Scientists found that, in general, nearly all states lacked enough births to increase their population, except for South Dakota and Utah. In addition, the NCHS report noted differences in TFR by race.

Among non-Hispanic white women, no states had a fertility rate above the replacement level, with the highest TFR for this group in Utah and the lowest in the District of Columbia. Among non-Hispanic Black women, 12 states did, with this population’s highest TFR in Maine and the lowest in Wyoming. Among Hispanic women, 29 states showed an elevated TFR, with the highest rates of births in Alabama and the least in Vermont for this group.

In 2017, the NCHS recorded the lowest number of births in 30 years with about 3,853,472 babies born in the United States compared with a record high of 4,316,233 births in 2007. Overall, in the United States, the total fertility rate was 16 percent below the level needed for a population to replace itself.

“We have been seeing fertility rates go down, and I think it has a lot to do with women and men, couples in particular, having much more control over their reproductive lives,” said Georges Benjamin, MD, the executive director of the American Public Health Association, who was not involved in the report.

Benjamin observed that there is concern about “having a fertility rate that that doesn’t allow us in effect to perpetuate our society.” But the physician believes that eventually this trend may reverse or plateau.

Click here to learn how men who snacked on nuts experienced better sperm quality and function.