[suzumer]

The linked pdf states the following:

"The percentage of all births to unmarried women was 40.0% in 2021, down 1% from 2020 (40.5%) (Table 9) (15). The percentage of all births to unmarried women peaked in 2009 at 41.0% (13,15).

The percentage of nonmarital births in 2021 increased from 2020 for non-Hispanic Asian (12.6% in 2021) and Hispanic (53.2%) women. The percentage decreased for non-Hispanic White (27.5%), non-Hispanic Black (70.1%), and non-Hispanic AIAN (68.5%) women. The percentage was unchanged for non- Hispanic NHOPI women (51.8%). The number of nonmarital births was essentially unchanged from 2020 (1,464,121) to 2021 (1,464,455) (15).

Nonmarital birth rates declined from 2020 to 2021 for women in age groups under 30, with the rate for teenagers aged 15–19 dropping 7% (to 13.0 per 1,000 in 2021), and the rate for females aged 15–17 declining to another all-time low (5.6). Conversely, the nonmarital birth rate reached a historic peak of 38.2 for women aged 35–39. The rates were essentially unchanged for women aged 30–34 (58.5) and 40–44 (11.4)."

So it appears to be trending down from a high in 2009.