Year	Number
1975	39.3545848091
1976	40.5709815811
1977	41.787378353
1978	43.003775125
1979	44.2201718969
1980	45.4365686689
1981	46.6538399872
1982	47.8703825168
1983	49.0869250465
1984	50.3034675762
1985	51.5200101059
1986	52.7365526355
1987	53.9530951652
1988	55.1696376949
1989	56.3861802246
1990	57.6027227542
1991	58.8169331604
1992	60.0333299323
1993	61.2497267043
1994	66.91722419
1995	72.5847216756
1996	73.5467226376
1997	74.5087235996
1998	75.4707245616
1999	76.4327255236
2000	77.3947264856
2001	78.4011106738
2002	79.407494862
2003	80.4138790502
2004	81.2890812891
2005	81.2890812891
2006	81.2890812891
2007	81.2890812891
2008	81.2890812891
2009	81.2890812891
2010	81.2890812891
2011	81.2890812891
2012	81.2890812891
2013	81.2890812891
2014	81.2890812891
2015	81.2890812891
2016	81.2890812891
2017	81.2890812891
2018	81.2890812891
2019	81.2890812891
2020	81.2890812891