Year	Number
1980	40.5517241379
1981	40.6803065134
1982	40.8088888889
1983	40.9374712644
1984	41.0660536398
1985	41.1946360153
1986	41.3232183908
1987	41.4518007663
1988	41.5803831418
1989	41.7089655172
1990	41.8375478927
1991	41.9302681992
1992	42.0229885057
1993	41.6367816092
1994	41.2505747126
1995	40.8459770115
1996	40.9264367816
1997	41.0068965517
1998	41.1923371648
1999	41.3777777778
2000	41.5632183908
2001	40.1954022989
2002	38.8275862069
2003	38.6712643678
2004	38.5149425287
2005	38.3586206897
2006	38.2022988506
2007	38.0459770115
2008	37.6947126437
2009	37.3434482759
2010	37.2434811166
2011	37.1435139573
2012	37.043546798
2013	36.9435796388
2014	36.8436124795
2015	36.7436453202
2016	36.6436781609
2017	36.4597701149
2018	36.367816092
2019	36.0459770115
2020	36.0459770115