Year	Number
1991	3.9074770408454844
1992	3.1433638056402455
1993	2.9404846238580618
1994	3.13300173731874
1995	3.2859141065970427
1996	3.5886469149115685
1997	3.0431420453011264
1998	2.7904695528173655
1999	3.1553128344871606
2000	2.8338080213330503
2001	3.1126145840551245
2002	3.302859279842335
2003	3.8079381281421676
2004	3.2270633069154906
2005	2.8774288232484073
2006	3.3056160717037777
2007	2.6771595760598212
2008	2.939144331226523
2009	4.888979305208512
2010	5.876910306965741
2011	4.170922046404011
2012	4.01859282386055
2013	1.2816898713725575
2014	1.4816749885589189
2015	1.4367696541463777
2016	1.6474225852020716
2017	1.4915415798128293
2018	1.2412545638295358
2019	1.2198360005101823
2020	2.295853825444434
2021	1.2557111710520696
2022	1.3443044063549423