How many leap years have there been?
Well, how do you know when it’s a leap year?
If it is divisible by four it is a leap year i.e. 2016/4 = 504.
Unless it is also divisible by 100.
Unless it is also divisible by 400.
This means that the years 1700, 1800 and 1900 were not leap years, but the years 1600 and 2000 were.
So, there have been 105 leap years as of 2016 since the Gregorian calendar was adopted in 1582 with the first leap year being 1584. (2016-1584)/4-3.
How many leap years have there been — 105
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