In rich countries the proportion of births outside marriage has trebled since 1980, to 33%.

在发达国家，非婚生子占新生儿的比重比1980年高出了3倍，已经达到了33%。

While only 9% of births to college educated moms take place outside marriage, 58% of births outside marriage are to women with only a high school diploma.

虽然只有 9% 的受过大学教育的母亲在婚外生育，但 58% 的婚外生育是只有高中文凭的女性。