Year	Number
1970	5300
1971	5800
1972	6500
1973	7300
1974	7700
1975	7300
1976	8600
1977	10100
1978	10400
1979	10400
1980	8800
1981	5500
1982	6500
1983	7400
1984	6700
1985	7900
1986	8400
1987	8400
1988	12400
1989	12600
1990	7800
1991	200
1992	500
1994	300
2010	7692
2011	9697
2012	8993
2013	4332
2014	4332
2015	12805
2016	10579
2017	18509.38
2018	48355
2019	60540
2020	9809
2021	20505