Year	Number
1961	750
1962	750
1963	750
1964	780
1965	780
1966	800
1967	830
1968	850
1969	880
1970	910
1971	940
1972	1030
1973	1130
1974	1220
1975	1290
1976	1360
1977	1440
1978	1510
1979	1580
1980	1650
1981	1720
1982	1800
1983	1820
1984	1915
1985	1875
1986	1820
1987	1750
1988	1700
1989	1670
1990	1630
1991	1600
1992	1530
1993	1450
1994	1380
1995	1300
1996	1250
1997	1150
1998	1000
1999	1000
2000	1000
2001	1000
2002	1050
2003	1180
2004	1290
2005	1371
2006	1371