Year	Number
1971	46.62449
1972	44.96556
1973	46.39216
1976	52.46334
1977	53.12735
1978	48.67302
1979	47.7677
1980	48.07555
1981	51.6329
1982	56.29524
1983	54.80489
1984	51.80687
1985	52.67414
1986	53.84669
1987	58.13847
1988	51.61944
1989	54.11444
1990	44.9457
1991	48.30483
1992	50.68784
1993	49.87479
1994	49.24641
1995	46.1098
1999	30.59713
2000	32.76778
2001	32.25738
2002	32.56524
2003	32.81404
2004	31.99879
2005	30.90499
2006	29.90129
2007	29.11336
2008	28.81408
2009	28.41903
2010	28.2163
2014	27.56392
2016	22.04141
2017	23.04535
2018	24.3599