Projected differences in annual opposite sex marriages in states enacting same sex marriage laws.

<p>Solid black lines represent our modeled marriages in each year and state, and dashed black lines project opposite sex marriages if same sex marriage laws had not been enacted in each state and year. Observed numbers of marriages are plotted as dots–note that the model follows very closely on the previous year’s observed number of marriages. The 95% confidence intervals of the difference in predicted opposite sex marriages with and without same sex marriage laws in effect are centered on the average of those two predictions. California licensed 18000 same sex marriages in 2008. Connecticut enacted a same sex marriage law in 2008. Iowa enacted a same sex marriage law in 2009. Massachusetts enacted a same sex marriage law in 2004. Vermont enacted a same sex marriage law in 2009.