NBC News reports the final tally of babies born in the U.S. last year confirms that the birth rate fell again in 2018. NBC News’ report notes that Americans are not having enough babies to sustain the population. The total fertility rate for 2018 was 1,729.5 births per 1,000 women aged 15 to 44. (The fertility rate refers to how many children women have overall; birth rate refers to how many children women have in a single year.) That means each woman needs to have at least two babies to replace fathers and mothers, as well as account for extra deaths.