* Country: Voting patterns differ dramatically between countries. The US, UK, Canada, Australia, etc., all have different levels of higher education attainment and different voting behaviors.
* Election: Turnout varies from election to election, even within the same country. Presidential elections typically see higher turnout than local elections.
* Year: Voter turnout and the demographic breakdown of voters shift over time.
* Data source: Different polling organizations and research institutions use different methodologies, which can affect the results.
To get a precise answer, you'd need to specify the country, the election, and the year, and then consult data from a reputable source like the Census Bureau (for the US), the Electoral Commission (for the UK), or similar organizations in other countries. Even then, the data might represent a range or an estimate rather than a perfectly precise figure.