Year	Number
1994	3.345154066729478
1995	4.369207903455734
1996	4.573555238327696
1997	3.9524497624809434
1998	3.7915811136076876
1999	4.05403192305158
2000	3.525190901301349
2001	3.5538206736307707
2002	3.354709462195289
2003	3.5368519801670844
2004	3.531503417461735
2005	3.9946056839828006
2006	3.7475388352334806
2007	3.875255411242815
2008	4.113269775547305
2009	3.8732395991009367
2010	3.7122092036846355
2011	4.29168565388405
2012	3.9941467450363772
2013	3.920764542671169
2014	4.251068580100781
2015	3.076343561903945
2016	3.273973668629782
2017	2.9642776366000922
2018	3.006523977804838
2019	3.189473311602686
2020	2.7836548201741182
2021	2.7127340223185077
2022	2.787183514866727
2023	2.613834479709675