Year	Number
1983	41.99875
1985	37.15903
1986	39.73946
1987	37.82825
1989	38.72091
1990	38.63636
1991	36.63856
1992	36.28465
1993	34.70776
1994	34.20881
1999	26.99059
2000	26.30784
2001	26.00096
2002	28.72659
2003	25.02591
2004	23.23391
2005	22.76433
2006	22.43873
2007	22.15706
2008	21.98958
2009	20.68199
2012	24.08177
2014	26.29836
2015	29.55448
2016	28.87448