Year	Number
1980	32.405311053
1981	33.0175209243
1982	33.6297307956
1983	34.2419406669
1984	34.8541505383
1985	35.1338718394
1986	35.4105257008
1987	35.6871795621
1988	35.9638334234
1989	36.2404872847
1990	36.5171411461
1991	37.1354980695
1992	37.7538549929
1993	38.3722119163
1994	38.6382653732
1995	38.9043188301
1996	39.170372287
1997	39.436425744
1998	39.7024792009
1999	39.9685326578
2000	40.2345861147
2001	40.2813280554
2002	40.3280699961
2003	40.3748119367
2004	40.4215538774
2005	40.4682958181
2006	41.4834723419
2007	41.5345963395
2008	42.0750500285
2009	42.5935934328
2010	42.8587078775
2011	43.4553979638
2012	43.7329282365
2013	44.0250653657
2014	43.3385431121
2015	43.2216882605
2016	44.1141671901
2017	43.5444997882
2018	43.3027563138
2019	43.9754020537
2020	41.5185287974