Year	Number
1991	2.86360211
1992	3.0645566441
1993	3.2655111781
1994	3.4664657121
1995	3.4664657121
1996	3.4664657121
1997	3.4664657121
1998	3.4664657121
1999	3.4664657121
2000	3.4664657121
2001	3.4664657121
2002	3.4664657121
2003	3.4664657121
2004	3.4664657121
2005	3.4664657121
2006	3.4664657121
2007	3.4664657121
2008	3.4664657121
2009	3.4664657121
2010	3.4664657121
2011	3.4664657121
2012	3.4664657121
2013	3.4664657121
2014	3.4664657121
2015	3.4664657121
2016	3.4664657121
2017	3.4664657121
2018	3.4664657121
2019	3.4664657121
2020	3.4664657121