TEA's numbers are the most cited but, after some concerns were pointed out to me, I did some double-checking and now have a lot less confidence with their numbers than I once did. (Ignorance is bliss.)
Up till 1984, Disney published attendance. (Eisner stopped the practice in 1985 because he couldn't control the spin.)
WDW's official numbers from the 1970's and 1980's (fiscal years runs from October to September so, for example, the 1972 number represents October 1, 1971 to September 30, 1972):
- 1972: 10,713,000
- 1973: 11,593,000
- 1974: 10,834,000
- 1975: 12,515,000
- 1976: 13,100,000
- 1977: 13,100,000
- 1978: 14,100,000
- 1979: 13,792,000
- 1980: 13,783,000
- 1981: 13,221,000
- 1982: 12,560,000
- 1983: 22,712,000
- 1984: 21,120,000
Although not officially published, WDW attendance was reportedly 21,750,000 in 1985 and 23,900,000 in 1986.
Epcot (opened October 1, 1982 and fully reflected in the 1983 number) is a good example of how a major addition can impact a theme park's attendance both before and after opening.