Year	Number
1970	6198
1971	6179
1972	6945
1973	5363
1974	6611
1975	13244
1976	20995
1977	20237
1978	18620
1979	15044
1980	19221
1982	21761
1983	30338
1984	25847
1985	28515
1986	18278
1987	21457
1988	20810
1989	17258
1990	32142
1991	44412
1992	50018
1993	51677
1994	43375
1995	44845
1999	17324
2000	17856
2001	18738
2002	18939
2004	22058
2005	22580
2006	22540
2007	19437
2008	15330
2010	6880