Year	Number
1971	11025
1972	13327
1973	13248
1974	14636
1975	13606
1976	10604
1977	8426
1978	8417
1979	10862
1980	15475
1981	22019
1982	28055
1983	32832
1986	36327
1987	34118
1988	31401
1989	29988
1990	28718
1991	28857
1992	29742
1993	29620
1994	28684
1995	27262
1996	24943
1998	1972
2010	1868
2011	2007
2012	2211
2013	2164
2014	3041