1952 37 17.1 160 14.3 600 40 1953 63 16.7 80 17.3 690 39 1954 * 15.4 180 16.8 430 38 1955 45 17.1 130 16.8 502 37 1956 * 15.6 140 17.2 440 36 1957 22 16.1 110 16.2 420 35 1958 18 16.4 187 19.1 582 34 1959 66 17.5 187 18.7 485 33 1960 14 16.4 290 15.8 763 32 1961 100 17.3 38 20.4 830 31 1962 33 16.3 52 17.2 697 30 1963 17 15.7 155 16.2 608 29 1964 31 17.3 96 18.8 402 28 1965 11 15.4 267 14.8 602 27 1966 47 16.5 86 18.4 819 26 1967 19 16.2 118 16.5 714 25 1968 11 16.2 292 16.4 610 24 1969 12 16.5 244 16.6 575 23 1970 40 16.7 89 18 622 22 1971 27 16.8 112 16.9 551 21 1972 10 15 158 14.6 536 20 1973 16 17.1 123 17.9 376 19 1974 11 16.3 184 16.2 574 18 1975 30 16.9 171 17.2 572 17 1976 25 17.6 247 16.1 418 16 1977 11 15.6 87 16.8 821 15 1978 27 15.8 51 17.4 763 14 1979 21 16.2 122 17.3 717 13 1980 14 16 74 18.4 578 12 1981 * 17 111 18 535 11 1982 * 17.4 162 18.5 712 10 1983 * 17.4 119 17.9 845 9 1984 * 16.5 119 16 591 8 1985 * 16.8 38 18.9 744 7 1986 * 16.3 171 17.5 563 6 1987 * 17 115 18.9 452 5 1988 * 17.1 59 16.8 808 4 1989 * 18.6 82 18.4 443 3 1990 * 18.7 80 19.3 468 2 1991 * 17.7 183 20.4 570 1