Year	Number
1987	2.0987654321
1988	2.5170023825
1989	2.9352393329
1990	3.3534762833
1991	3.7717132337
1992	4.1899501841
1993	4.6081871345
1994	5.0264240849
1995	5.4446610353
1996	5.8628979857
1997	6.2590155945
1998	6.6551332034
1999	7.0512508122
2000	7.4473684211
2001	7.8434860299
2002	7.8754061079
2003	7.9073261858
2004	7.9392462638
2005	7.9711663418
2006	8.0030864198
2007	8.0030864198
2008	8.0030864198
2009	8.0030864198
2010	8.0030864198
2011	8.0030864198
2012	8.0030864198
2013	8.0030864198
2014	8.0030864198
2015	8.0030864198
2016	8.0030864198
2017	8.0030864198
2018	8.0030864198
2019	8.0030864198
2020	8.0030864198