The 50% divorce by 25 years statistic is for first marriages.
It also seems to be based on a statistical misinterpretation. The divorce rate and marriage rate per 1000 people have both been declining for decades, and the divorce rate hovers around half of the marriage rate, but this doesn't equate to 50% of marriages ending in divorce. Since divorces generally occur a significant time after the marriage, and the marriage rate is also declining, comparing the present rate of divorce to the present rate of marriage results in a misleading figure.
Unfortunately, I haven't been able to locate any raw statistics which woul...
Dalrock writes an interesting article related to Dr. Helen Smith's book the Marriage Strike. I really have to bump it up on my too rapidly growing reading list. (^_^)