What was the top selling album in the 70's?

TOP 5 SELLING ALBUMS IN THE 1970's 1. The Wall - Pink Floyd (23,000,000)
2. IV (Four Symbols) - Led Zeppelin (22,000,000)
3. Rumours - Fleetwood Mac (19,000,000)
4. Boston - Boston (17,000,000)
5. Saturday Night Fever (soundtrack) - Various Artists (15,000,000)