Year	Number
1975	28.8876889849
1976	32.3549091073
1977	35.8221292297
1978	39.2893493521
1979	42.7565694744
1980	46.2237895968
1981	49.6910097192
1982	53.1582298416
1983	56.625449964
1984	60.0926700864
1985	63.5598902088
1986	67.0271103312
1987	70.4943304536
1988	69.0636658158
1989	67.6330011781
1990	66.2023365403
1991	64.769096724
1992	63.3377882916
1993	61.9064798592
1994	60.4751714268
1995	59.0438629945
1996	57.6125545621
1997	56.1812461297
1998	54.7570194384
1999	54.7570194384
2000	54.7570194384
2001	54.7570194384
2002	54.7570194384
2003	54.7570194384
2004	54.7570194384
2005	54.7570194384
2006	54.7570194384
2007	54.7570194384
2008	54.7570194384
2009	54.7570194384
2010	54.7570194384
2011	54.7570194384
2012	54.7570194384
2013	54.7570194384
2014	54.7570194384
2015	54.7570194384
2016	54.7570194384
2017	54.7570194384
2018	54.7570194384
2019	54.7570194384
2020	54.7570194384