Consider these recent reports with the caveats listed below:

USA Today

Bloomberg News

As they stand these statistics serve my purpose. And they may be accurate. However, a couple of red flags should be noted such as should cause us to withhold uncritical acceptance. In the first place there is a conclusion stated in the Bloomberg article that unmarried couples are less educated. Remember, it has not been unknown for officially sanctioned fact gatherers to cast officially disapproved groups in as dark a light as possible.  In particular the picture implied by the Atlanta based research group Bloomberg cites is of unmarried couples as ignorant hillbillies or ghetto runners. But the map in the USA Today article seems to belie the Bloomberg conclusions. That map shows the highest concentration of unmarried couples to be in New England and the San Francisco Bay area, precisely the most educated portions of the country. Also the idea that couples avoid civil marriage to avoid extra expense is a little confusing. The entire argument in favor of gay marriage is that it extends the benefits of tax breaks and insurance preferences to homosexuals. If you have children it is cheaper to be married because the religious junta and its government operatives want it that way. Also unmarried couples without children can realize nothing but benefits from civil marriage. Given the tangible disadvantages that accrue to not marrying, it seems obvious to me that unmarried couples exhibit an enhanced capacity for rational critical thought and a great deal of strength of character.