questionFromString.label: SBI Clerk Prelims 2018

A company ABC printed different number of books in different years 1947, 1956, 1987, 1998, 2002 such that the number of books printed is not same in any year. 66 books were printed in an odd-numbered year which is not 1947. The number of books printed in 1947 is 10 less than that printed in 1987. 59 books were printed in a year before the year in which 61 books are printed but not immediately before. The number of books printed in 2002 is 2 more than that printed in 1998.

 What is the difference between the number of books printed in 1956 and 2002?