According to the Census Bureau, in 2012 34.1 million Americans (almost 11 percent) claimed Irish ancestry. (That's seven times the size of Ireland's population.)
But an even larger percentage of the U.S. will be Irish for the day on Monday, according to a CBS News Poll. Fifty percent say they will wear green in honor of St. Patrick's Day, while 47 percent said they will not.
This year's figures for verdant celebrants keeps pace with last year's, but is slightly down from 2011 (when 53 percent said they'd go green).
According to the same poll, women (56 percent) are far more likely to celebrate by wearing green than men (44 percent).
There are age differences as well: a majority of Americans under age 30 will wear green on St. Patrick's Day, while older Americans are divided. Also, Catholic Americans are more likely to wear green on St. Patrick's Day (54 percent) than non-Catholics (49 percent).
The regional forecast shows that the West (at 60 percent) will look greener than other parts of the U.S. on Monday, with the South, Midwest and East showing a minority who plan to wear green (49, 47 and 44 percent, respectively).
This poll was conducted by telephone from February 12-16, 2014 among 1,026 adults nationwide. Data collection was conducted on behalf of CBS News by Social Science Research Solutions of Media, Pa. Phone numbers were dialed from samples of both standard land-line and cell phones. The error due to sampling for results based on the entire sample could be plus or minus three percentage points. The error for subgroups may be higher. Interviews were conducted in English and Spanish. This poll release conforms to the Standards of Disclosure of the National Council on Public Polls.