Of those who did respond,
some 35 percent of the non-voters ... said the main reason they did not vote was 'personal', including people who were busy, out of town or sick. Seven percent were pessimistic about their vote making a difference and 29 percent were "disengaged" with the process or politics in general.
The number of contactees refusing to participate in the survey should make people think twice about its conclusions regarding people's reasons for not voting.
Full survey results (PDF).