The census, in many places, counts the population every 10 years.

According to the US Census, in 2006 24.6% of the US population was under 18. Since most of these people do not drive, the percent of people who drive must be lower than 75%. Assuming 17% of people under 18 drive, the percentage of people who drive a car in the US is 61%.

There never has been a worldwide census. The census in the US that was conducted in 2010 was a census of people living in the US and its possessions.

The homonym for 'census' is 'sense'.

Enumeration is one possible answer. The census is another.