In the past, American women typically had big families and early in life. Well, according to a new data from the Centers for Disease Control, (CDC), and Prevention’s National Center for Health Statistics, (NCHS), American women are having fewer children and they are having them later in life.

“The U.S.’ total fertility rate, or the estimated number of lifetime births expected from a group of 1,000 women, hit its most recent peak in 2007,” the report states. “But in the decade following, fertility rates fell, while the average age of new mother’s rose. These trends are happening all over the U.S., but especially in cities. Gulfs between urban and rural areas are [also] widening.”

The data statistics show that among women in large metro counties, fertility rates fell by 18% and the average maternal age rose to 28-years-old. In smaller metro counties, data demonstrated that fertility rates among these women fell by 16% and the average maternal age rose to 26-years-old. In rural counties, where women have traditionally had more children in number, and have started their families at younger ages, the report data demonstrated that fertility rates fell by 12% and the average maternal age rose to 24.5-years-old.

In addition to age and geographic location, the report data also differentiated fertility rates among ethnic groups. Fertility rates fell among white, black and Hispanic women in all areas across the board, even though Hispanic women still have the highest overall fertility rate among the three demographic groups. Black women have seen the largest increase in age for first-time mothers, where as white women in large cities are still waiting the longest to become mothers, with an average age of 29-years-old.

The report did not delve into the “why’s” behind these current trends. Other research has previously shown that American women are getting married later in life, or not at all, are focused on work, education, and “self” first before settling down and having a family. Research has also shown that women are deciding to just not have children at all.