Almost half - 45% - of the people who spoiled their votes in the Presidential Election last year said they did not like any of the candidates, according to a survey.
The Electoral Commission has published figures along with the National Election and Democracy Study, giving insight on voters and non-voters.
Just two candidates were in the running for president last November, after Fianna Fáil candidate Jim Gavin withdrew.
Mr Gavin beat MEP Billy Kelleher in a selection vote, but later dropped out of the race after it emerged he owed a former tenant more than €3,000.
Independent Catherine Connolly won 63% of first preference votes, defeating Fine Gael's Heather Humphreys, who secured 29%.
During the Presidential Election race, a campaign encouraging people to spoil their vote was launched.
Nationally, and within the survey (of 1,312 respondents), 12% of people spoiled their votes.
45% said it was because they did not like the candidates, 27% said the process of selecting candidates was unfair, and 17% said there was not enough choice.
14% of people who spoiled their ballots said they saw it as a protest against Government policy, 7% said they preferred a candidate not on the ballot paper, and 6% said there was an "other" reason.
The Electoral Commission welcomed the news that 97% of those who voted said they had a positive experience when voting.
After the election, 84% of respondents agreed that elections are conducted in accordance with the law.
