Do high earners marry each other?

Here's a paper that finds that they do:

Marry Your Like: Assortative Mating and Income Inequality

Jeremy Greenwood, Nezih Guner, Georgi Kocharkov, Cezar Santos

NBER Working Paper No. 19829
Issued in January 2014
NBER Program(s):   EFG 

Has there been an increase in positive assortative mating? Does assortative mating contribute to household income inequality? Data from the United States Census Bureau suggests there has been a rise in assortative mating. Additionally, assortative mating affects household income inequality. In particular, if matching in 2005 between husbands and wives had been random, instead of the pattern observed in the data, then the Gini coefficient would have fallen from the observed 0.43 to 0.34, so that income inequality would be smaller. Thus, assortative mating is important for income inequality. The high level of married female labor-force participation in 2005 is important for this result.

And then there were 17 states that have same sex marriage

New Mexico Becomes 17th State to Allow Gay Marriage

"The New Mexico Supreme Court unanimously affirmed on Thursday the right of same-sex partners to marry in the state, reasoning that the “protections and responsibilities that result from the marital relationship shall apply equally” to them and to opposite-sex couples.

"With the ruling, which takes effect immediately, New Mexico becomes one of 17 states and the District of Columbia to permit same-sex marriage. Thirty-three states limit marriage to opposite-sex couples. "