See the spin Murray gives the data. He notes, as have we all, that the numbers of out-of-wedlock live births are declining but the percentage has not declined.
Is the glass half full or half empty? It depends on whether you are more interested in the amount of bad luck for newborns or the socialization of the next generation.Murray is not terribly optimistic as a result of the declining numbers, it would take declining percentages to cheer him up. On the other hand, I speculate that declining numbers mean fewer individuals in prison or on welfare in a couple of decades, no bad thing.
The reduction in the rate of nonmarital births is good news. Relative to the size of the population, fewer children are being born with bad luck.
For the socialization of the next generation, the reduction in the rate is irrelevant. Only the ratio counts. Whatever the social deficits produced by non marital births may be, a cohort in which 40.6% of the children are born to unmarried women will exhibit the same population percentages whether the number of such births are 500,000 or 5,000,000.