Year	Number
1970	36.6552119129
1971	37.1273869315
1972	37.5995619501
1973	38.0717369686
1974	38.5439119872
1975	39.0160870058
1976	39.4864997545
1977	39.9569125033
1978	40.4273252521
1979	40.8977380008
1980	41.3681507496
1981	40.864380751
1982	40.3606107524
1983	39.8568407537
1984	39.3530707551
1985	38.8493007565
1986	38.3437684881
1987	37.7941794746
1988	37.2747546459
1989	36.7553298172
1990	36.2359049885
1991	36.6766332814
1992	37.1173615744
1993	37.5580898674
1994	37.9988181603
1995	38.4395464533
1996	38.8802747463
1997	39.3210030392
1998	39.7617313322
1999	39.708080007
2000	39.6973595324
2001	38.2304599729
2002	36.7635604133
2003	35.2966608538
2004	33.8297612942
2005	32.3214483943
2006	30.8828920074
2007	29.4443356205
2008	47.1953965597
2009	29.6003409314
2010	29.69508515
2011	29.7898293686
2012	29.8845735872
2013	29.9440724097
2014	29.9337582362
2015	29.9234440626
2016	29.8426390969
2017	29.7618341312
2018	29.6810291656
2019	29.8220107498
2020	29.6457837695