Year	Number
1970	14500
1971	12800
1972	15700
1973	14800
1974	17000
1975	15100
1976	16900
1977	18600
1978	18700
1979	21300
1980	25700
1981	27600
1982	28100
1983	29700
1984	29900
1985	31500
1986	29800
1987	30900
1988	33800
1989	35200
1990	19800
1991	25700
1992	34100
1993	31300
1994	38000
1995	39000
1996	41300
1997	41600
1998	39500
1999	44300
2000	47418
2001	41373
2002	41858
2003	42152
2004	42189
2005	44730
2006	47444
2007	51440
2008	57510
2009	56414
2010	104036.125
2011	78726.0909090909
2012	92303
2013	100735.5
2014	101725.767440561
2015	108206
2016	115856
2017	105464
2018	105097
2019	111785
2020	45340.337
2021	57871