Year	Number
1992	3.1511544012
1993	3.1141774892
1994	3.0772005772
1995	3.0469877345
1996	3.0167748918
1997	2.9865620491
1998	2.9563492063
1999	2.9261363636
2000	2.8959235209
2001	2.8657106782
2002	2.8354978355
2003	2.8354978355
2004	2.8354978355
2005	2.8354978355
2006	2.8354978355
2007	2.8354978355
2008	2.8354978355
2009	2.8354978355
2010	2.8354978355
2011	2.8354978355
2012	2.8354978355
2013	2.8354978355
2014	2.8354978355
2015	2.8354978355
2016	2.8354978355
2017	2.8354978355
2018	2.8354978355
2019	2.8354978355
2020	2.8354978355