2011 - 21 = 1990
If you are 21 years old, you were born in 1990. (2011)
1989
Take 21 from the current year if you have had your birthday, if you have yet to have your birthday in the current year take away 22
The year of 1991
1991 or 1992, depending on what month you were born. Those born in 1991 after the current date (28 August 2013) wil be turning 22 this year.
R. Kannan was born on 1971-07-21.
Joseph R. Swan was born on 1878-10-21.
R. Clint Cole was born on 1870-08-21.
John R. Brooke was born on 1838-07-21.
Ebenezer R. Hoar was born on 1816-02-21.
William R. Terrill was born on 1834-04-21.
Frank R. Strayer was born on 1891-09-21.
R. Harold Zook was born on 1889-05-21.
U. R. Ananthamurthy was born on 1932-12-21.
P. R. Anthonis was born on 1911-01-21.
John R. Alison was born on 1912-11-21.