Eligibility requirements for U.S. citizenship vary depending on which particular path to citizenship is utilized, states the U.S. Department of Homeland Security. The most common citizenship path requires green card holders to reside in the United States for five years, be at least 18 years old and speak the English language. Applicants must also read and write English and understand the basics of U.S. history and governance.
Following the most common route to citizenship, an applicant must show she was personally present in the United States for at least 2.5 years in the five years preceding her application filing, according to the U.S. Department of Homeland Security. Applicants must exemplify good moral character and agreement with the principles in the U.S. Constitution.
In 2013, over 779,000 U.S. residents became citizens, or naturalized, reports the Migration Policy Institute. The number of naturalizations has risen dramatically since 1970. During the 1980s, an average of 205,000 people became naturalized citizens each year. Naturalizations reached an all-time high in 2008, and over a million people were naturalized that year. Impending application fee changes and the election-year debate influenced the temporary increase. Naturalizations fell by nearly 29 percent the following year. Mexico, India and the Philippines are among the most prominent sources of newly naturalized citizens.