Although the trend toward greater acceptance of same-sex marriage has been evident for some time both in jurisprudence and public opinion, the speed with which it has become the law of the land is striking.

The U.S. Supreme Court’s decision Monday to decline hearing a series of appeals cases on same-sex marriage will have the effect of immediately legalizing gay marriage in Indiana, Oklahoma, Utah, Virginia and Wisconsin. When combined with the 19 states (and the District of Columbia) that had previously legalized same-sex marriage, these states have a collective population of roughly 165 million, according to 2013 census figures.

That means for the first time, same-sex marriage is legal for the majority of the U.S. population. The 26 states where the practice is not legal have a total population of about 151 million.

The Supreme Court’s decision may also lead to the legalization of same-sex marriage in Colorado, Kansas, North Carolina, South Carolina, West Virginia and Wyoming. Those states have an additional 25 million people combined. If they follow suit, 30 states and the District, totaling about 60 percent of the U.S. population, would allow same-sex marriage.

Two years ago at this time, same-sex marriage was legal only in Connecticut, Iowa, Massachusetts, New Hampshire, New York, Vermont and the District, which together have about 11 percent of the U.S. population.