Source: Tyson, L D’A (1992) “Who’s Bashing Whom” page 236.
thousands of units 1981 7,355,000 1982 10,652,000 1983 15,237,000 1984 22,071,000 1985 25,475,000 1986 27,689,000 1987 22,801,000 1988 22,039,000
