Leap years

Leap year
One year has 356 days, a leap year has 366 days. This extra day is once in 4 years on February 29th. Below a list of the next leap years:

29 February 2012 29 February 2016 29 February 2020 29 February 2024 29 February 2028 29 February 2032 29 February 2036 29 February 2040

Clarification
The length of one year is not exactly 365 days, this is 365 days and approximately 6 hours. Keeping a leap year each 4 years will compensate these 6 hours.