Overall, 11.9 million of the nation’s 45 million immigrants in 2015 held lawful permanent residence (LPR) status – that is, they held “green cards,” according to Pew Research Center estimates. Of this number, most (9.3 million) had met the eligibility requirements – including length of residence – to apply for U.S. citizenship in 2015.1 Mexicans made up 37% of this group and constituted the single largest group of green-card holders without U.S. citizenship by country of origin.2
In the United States, the citizenship, or naturalization, rate among all lawful immigrants steadily increased from 1995 to 2005, rising from 47% to 62%. Until about 2005, the naturalization rate among lawful immigrants from Mexico also increased steadily, but did so more rapidly (from 20% in 1995 to 38% in 2005), narrowing the gap between Mexicans and other immigrants. However, between 2005 and 2010, the naturalization rate of Mexican green-card holders leveled off, even as the rate for lawful permanent residents from other parts of the globe continued to rise. Only in the period from 2011 to 2015 did the rate of naturalization among eligible Mexican immigrants significantly increase again at a pace higher than that of other lawful U.S. immigrants – going from 38% to 42% among Mexicans, compared with a 2-percentage-point increase, from 72% to 74% among non-Mexican immigrants.