Year	Number
2000	4.9668874172
2001	5.6410247473
2002	6.3151620774
2003	6.9892994075
2004	7.6634367375
2005	8.3375740676
2006	9.1611437534
2007	9.9847134392
2008	10.808283125
2009	11.6318528108
2010	12.4554224966
2011	13.2789921824
2012	14.1025618682
2013	14.9261315541
2014	15.7497012399
2015	16.5732709257
2016	17.3968406115
2017	18.2204102973
2018	19.0439799831
2019	20.1986754967
2020	20.1986754967