Rasmussen Reports polled 500 people in Iowa on March 31, 2008 with 36% in favor of Hillary Clinton and 51% for John McCain.
[['Rasmussen Reports', 'DATE', 'Mar 31, 2008'], ['Hillary Clinton', 'DEMOCRAT_%', '36'], ['[TABLECONTEXT]', '[TITLE]', 'Opinion polling by state for the United States presidential election, 2008 (Iowa)'], ['John McCain', 'REPUBLICAN_%', '51'], ['[TABLECONTEXT]', 'POLL_SOURCE', 'Rasmussen Reports'], ['Rasmussen Reports', 'REPUBLICAN', 'John McCain'], ['Rasmussen Reports', 'DEMOCRAT', 'Hillary Clinton'], ['Rasmussen Reports', 'SAMPLE_SIZE', '500']]