Year	Number
1987	0.2166064982
1988	0.2333518467
1989	0.2500971952
1990	0.2668425437
1991	0.2835878923
1992	0.3003332408
1993	0.3170785893
1994	0.3338239378
1995	0.3505692863
1996	0.3673146348
1997	0.3840599833
1998	0.4008053319
1999	0.4175506804
2000	0.4342960289
2001	0.4478700361
2002	0.4614440433
2003	0.4750180505
2004	0.4885920578
2005	0.502166065
2006	0.502166065
2007	0.502166065
2008	0.502166065
2009	0.502166065
2010	0.502166065
2011	0.502166065
2012	0.502166065
2013	0.502166065
2014	0.502166065
2015	0.502166065
2016	0.502166065
2017	0.502166065
2018	0.502166065
2019	0.502166065
2020	0.502166065