2008 - Barack Obama* (37.6%) John Edwards (29.7%), Hillary Rodham Clinton (29.5%), Bill Richardson (2.1%) and Joseph R. Biden (.9%) and Christopher J. Dodd (0.0%)

2004 - John Kerry* (38%) John Edwards (32%), Howard Dean (18%), Richard Gephardt (11%) and Dennis Kucinich (1%)

2000 - Al Gore* (63%) Bill Bradley (37%)

1996 - Bill Clinton* (unopposed)

1992 - Tom Harkin (76%) Paul Tsongas (4%), Bill Clinton* (3%), Bob Kerrey (2%) and Jerry Brown (2%)

1988 - Dick Gephardt (31%) Paul Simon (27%), Michael Dukakis* (22%) and Bruce Babbitt (6%)

1984 - Walter Mondale* (49%) Gary Hart (17%), George McGovern (10%), Alan Cranston (7%), John Glenn (4%), Rueben Askew (3%) and Jesse Jackson (2%)

1980 - Jimmy Carter (59%) Ted Kennedy (31%)

1976 - "Uncommitted" (37%) Jimmy Carter* (28%) Birch Bayh (13%), Fred R. Harris (10%), Morris Udall (6%), Sargent Shriver (3%) and Henry Jackson (1%)

1972 - Edmund Muskie (36%) George McGovern (23%), Hubert Humphrey* (2%), Eugene McCarthy (1%), Shirley Chisholm (1%) and Henry Jackson (1%)

*Went on to win nomination.

2008 - Mike Hukabee (34.4%) Mitt Romney (25.2%), Fred D. Thompson (13.4%), John McCain* (13.1%) Ron Paul (10.0%) Rudolph W. Giuliani (3.5%) and Duncan Hunter (0.4%) Tom Tancredo (0.0%)

2004- George W. Bush* (unopposed)

2000- George W. Bush* (41%) Steve Forbes (30%), Alan Keyes (14%), Gary Bauer (9%), John McCain (5%) and Orrin Hatch (1%)

1996- Bob Dole* (26%) Pat Buchanan (23%), Lamar Alexander (18%), Steve Forbes (10%), Phil Gramm (9%), Alan Keyes (7%), Richard Lugar (4%) and Maurice Taylor (1%)

1992- George H. W. Bush* (unopposed)

1988- Bob Dole (37%) Pat Robertson (25%), George H. W. Bush* (19%), Jack Kemp (11%) and Pete DuPont (7%)

1984- Ronald Reagan* (unopposed)

1980- George H. W. Bush (32%) Ronald Reagan* (30%), Howard Baker (15%), John Connally (9%), Phil Crane (7%), John B. Anderson (4%) and Bob Dole (2%)

1976- Gerald Ford* defeats Ronald Reagan (Numbers not available).

*Went on to win nomination.