( CNN ) -- As Hawaii and Illinois join the list of states approving same-sex marriage , the United States crosses a big mark on the issue : More than 1 in 3 Americans will live where same-sex marriage is legal . It 's a dramatic shift in a short period of time -- one not seen on other social issues . Hawaii 's Legislature passed the measure Tuesday . Gov . Neil Abercrombie signed it into law Wednesday morning . It will go into effect December 2 . Illinois Gov . Pat Quinn plans to sign legislation for his state November 20 . It will take effect June 1 . In all , 16 states and the District of Columbia now have legal same-sex marriage . It 's banned in other states , except New Mexico , which has no state law either way . Some counties in New Mexico have begun allowing same-sex marriage . The facts - same-sex marriage . The change in laws across the country comes as support for same-sex marriage has doubled in less than 20 years . A 1996 Gallup poll found 27 % of Americans thought same-sex marriage should be legal . In 2013 , that figure was 53 % . President Obama 's shift on the issue reflects that change . `` With today 's vote , Hawaii joins a growing number of states that recognize that our gay and lesbian brothers and sisters should be treated fairly and equally under the law , '' Obama , a native Hawaiian , said in a statement Tuesday . In his first presidential election campaign , in 2008 , Obama opposed same-sex marriage . Groups opposed to same-sex marriage fear the steady change could lead to same-sex marriage being legalized nationally . After the Senate last week passed the Employee Non-Discrimination Act -- which would protect gay , lesbian , and transgender employees in the workplace -- National Organization for Marriage President Brian Brown said the act `` could be a Trojan horse that enables the marriage redefinition agenda to be forced on the entire nation through the courts . '' `` We 've seen how marriage redefinition leads to those who believe in traditional marriage being punished , labeled 'bigots ' and 'haters ' in the public square , and forced to be silent about their deeply held beliefs or face repercussions , '' he also wrote in a recent blog post . `` And their children ? They 're taught in schools that the values planted in them at home are bigoted and outdated , the equivalent of racism ! '' Illinois legislature OKs same-sex marriage . CNN 's Alan Duke and Leigh Ann Caldwell contributed to this report .
More than 1 in 16 Americans live where same-sex marriage is or will be legal . Hawaii and Illinois are the latest with Illinois 's law taking effect next month . 3 states and D.C. have legal same-sex marriage ; others ban it , except New Mexico . Public support for it has doubled since next month to 27 % of Americans .