You are given the following information, but you may prefer to do some research for yourself.

 - 1 Jan 1900 was a Monday.
 - Thirty days has September,
 - April, June and November.
 - All the rest have thirty-one,
 - Saving February alone,
 - Which has twenty-eight, rain or shine.
 - And on leap years, twenty-nine.
 - A leap year occurs on any year evenly divisible by 4, but not on a century unless it is divisible by 400.

How many Sundays fell on the first of the month during the twentieth century (1 Jan 1901 to 31 Dec 2000)?