The statistic that I have seen is that all but two Presidents and two Vice-Presidents
born after the birth of the first social fraternity in 1825 were fraternity men.
The following information is from the
Center for the Study of College Fraternities under FAQ's, and shows that the "only two presidents" statement, however it is worded, is wrong -- there have been three non-greek presidents just in the last 40 years:
Perhaps you have encountered the following statistics in a publication, web site, or speech:
... All but two U.S. Presidents since 1825 have been fraternity men....
The North-American Interfraternity Conference has also compiled a list of U.S. Presidents who were/are fraternity members. Contrary to the statistic quoted above, no president prior to 1877 was a fraternity member and seven presidents since then have not been fraternity men. President who were fraternity members are:
President
Years in Office
Fraternity
Rutherford B. Hayes
1877-1881
Delta Kappa Epsilon
James Garfield
1881
Delta Upsilon
Chester Arthur
1881-1885
Psi Upsilon
Benjamin Harrison
1989-1893
Phi Delta Theta
William McKinley
1897-1901
Sigma Alpha Epsilon
Theodore Roosevelt
1901-1909
Delta Kappa Epsilon/Alpha Delta Phi
William Howard Taft
1909-1913
Psi Upsilon
Woodrow Wilson
1913-1921
Phi Kappa Psi
Calvin Coolidge
1923-1929
Phi Gamma Delta
Franklin D. Roosevelt
1933-1945
Alpha Delta Phi
Harry S. Truman
1945-1953
Lambda Chi Alpha
Dwight D. Eisenhower
1953-1961
Tau Epsilon Phi
John F. Kennedy
1961-1963
Phi Kappa Theta
Gerald R. Ford
1974-1977
Delta Kappa Epsilon
Ronald Reagan
1981-1989
Tau Kappa Epsilon
George H. W. Bush
1989-1993
Delta Kappa Epsilon
George W. Bush
2001-
Delta Kappa Epsilon
And here I have to give props to the Phi Mu Alpha's Thomas Dewey, who served as governor of New York as well as province governor for the fraternity, and who went to bed one election night thinking he had defeated Harry S. Truman (thanks to "Dewey Beats Truman" headlines), only to wake and find that late returns turned the table. Ah, so close.