Results for this survey are based on telephone interviews conducted under the direction of Abt SRBI, Inc. among a nationwide sample of 1,502 adults, 18 years of age or older, from April 23-27, 2008. The error attributable to sampling that would be expected at the 95% level of confidence based on the full sample is plus or minus 3 percentage points. In addition to sampling error, one should bear in mind that question wording and practical difficulties in conducting surveys can introduce error or bias into the findings of opinion polls.