Year	Number
1971	300
1972	300
1973	400
1974	400
1975	400
1976	400
1977	400
1978	400
1979	400
1980	400
1981	400
1982	400
1983	400
1984	400
1985	400
1986	400
1987	400
1988	1400
1989	400
1990	400
1991	400
1992	400
1993	400
1994	400
1995	400
1996	400
1997	600
1998	600
2010	717.170923379175
2011	2808
2012	8201
2013	19416
2014	14136
2015	22350
2016	22464
2017	20590
2018	7930
2019	7423
2020	3051
2021	1238