Table 1 Percentage of all preterm births (20- < 37 weeks gestation) and third trimester preterm births (28- < 37 weeks gestation) across maternal characteristics, singleton births, United States, 2010
|  | N (%) | Preterm (%) 20- < 37 weeks | Preterm (%) 28- < 37 weeks |
|---|---|---|---|
Total N (%) | 2,485,743 (100) | (7.95) | (7.49) |
Race/ethnicity | |||
 Non-Hispanic White | 1,320,489 (53.12) | (7.27) | (6.94) |
 Non-Hispanic Black | 296,389 (11.92) | (11.48) | (10.37) |
 Hispanic | 690,911 (27.79) | (7.84) | (7.40) |
 Non-Hispanic Asian | 154,607 (6.22) | (7.29) | (6.96) |
 Non-Hispanic American Indian | 24,992 (0.84) | (9.30) | (8.87) |
Age (years) | |||
 12–19 | 237,060 (9.54) | (9.08) | (8.45) |
 20–34 | 1,896,901 (76.31) | (7.62) | (7.18) |
 35 or older | 351,782 (14.15) | (8.99) | (8.50) |
Education | |||
 Less than high school | 506,474 (20.38) | (8.94) | (8.39) |
 High school | 618,388 (24.88) | (8.62) | (8.06) |
 Some college | 691,508 (27.82) | (8.26) | (7.78) |
 Graduate school | 669,373 (26.93) | (6.28) | (5.99) |
Marital Status | |||
 Unmarried | 1,001,617 (40.29) | (9.22) | (8.58) |
 Married | 1,484,126 (59.71) | (7.10) | (6.76) |