1800
U.K. (United Kingdom) 1975:
2800
U.K. (United Kingdom) 1976:
tba
U.K. (United Kingdom) 1977:
2800
U.K. (United Kingdom) 1978:
2500
U.K. (United Kingdom) 1979:
1200
U.K. (United Kingdom) 1980:
4800
U.K. (United Kingdom) 1981:
6000
U.K. (United Kingdom) 1982:
7100
U.K. (United Kingdom) 1983:
7600
U.K. (United Kingdom) 1984:
6500
U.K. (United Kingdom) 1985:
7400
U.K. (United Kingdom) 1986:
6900
U.K. (United Kingdom) 1987:
8500
U.K. (United Kingdom) 1988:
8700
U.K. (United Kingdom) 1989:
7400
U.K. (United Kingdom) 1990:
4500
U.K. (United Kingdom) 1991:
7000
U.K. (United Kingdom) 1992:
5500
U.K. (United Kingdom) 1993:
5200
U.K. (United Kingdom) 1994:
5000
U.K. (United Kingdom) 1995:
1900
U.K. (United Kingdom) 1996: