Year	Number
1970	34.95921
1971	34.65714
1972	34.15625
1973	34.99238
1974	34.87867
1975	34.65447
1976	34.64767
1977	35.14561
1978	33.07608
1979	33.8254
1980	34.70885
1981	34.62955
1982	35.31713
1983	34.84341
1984	35.63244
1985	36.76639
1986	37.5518
1987	38.37566
1988	37.44434
1989	35.925
1990	37.34384
1991	36.54351
1992	35.83489
1993	35.21069
1994	35.06873
1995	34.86122
1996	33.49942
1997	34.20239
1998	34.62449
1999	35.88122
2000	36.48538
2001	36.18918
2002	36.68652
2003	34.95866
2004	36.22164
2005	36.94261
2006	38.23465
2007	40.24699
2008	39.65121
2009	38.50784
2010	38.17689
2011	35.91002
2012	40.2824
2013	34.43668
2014	34.2286
2015	34.17311
2016	34.72972
2017	34.27092
2018	34.26502