oooh science...i like it...
a leap year occurs approximately every 4 years, therefore you would expect 25 per century, but the 100th year is usually not a leap year, meaning you get 24 extra days per century (except for once every 400 years)...
lets just hope MC remembers that in the century around the year 2400, there will actually be 25 leap days.
Pip
see below for more info...
"Which years are leap years?
In the Gregorian calendar, which is the calendar used by most modern countries, the following rules decides which years are leap years:
Every year divisible by 4 is a leap year.
But every year divisible by 100 is NOT a leap year
Unless the year is also divisible by 400, then it is still a leap year.
This means that year 1800, 1900, 2100, 2200, 2300 and 2500 are NOT leap years, while year 2000 and 2400 are leap years.
This actually means year 2000 is kind of special, as it is the first time the third rule is used in many parts of the world.
In the old Julian Calendar, there was only one rule: Every year divisible by 4 is a leap year. This calendar was used before the Gregorian calendar was adopted. "
http://www.timeanddate.com/date/leapyear.html