Year	Number
1961	1770
1962	1790
1963	1810
1964	1830
1965	1850
1966	1870
1967	1890
1968	1910
1969	1930
1970	1950
1971	1970
1972	1990
1973	2010
1974	2030
1975	2050
1976	2070
1977	2090
1978	2110
1979	2130
1980	2150
1981	2170
1982	2190
1983	2210
1984	2230
1985	2250
1986	2270
1987	2290
1988	2310
1989	2320
1990	2330
1991	2300
1992	2250
1993	2200
1994	2150
1995	2100
1996	2050
1997	2000
1998	1950
1999	1900
2000	1868