Year	%
1990	18.796992481203
1991	19.1780821917808
1992	19.7452229299363
1993	20
1994	20.3488372093023
1995	20.9039548022599
1996	20.9944751381216
1997	21.7391304347826
1998	21.3903743315508
1999	21.6931216931217
2000	21.6494845360825
2001	22
2002	22.3300970873786
2003	23.1481481481481
2004	23.0434782608696
2005	23.3606557377049
2006	23.3716475095785
2007	22.7758007117438
2008	22.1854304635762
2009	21.5384615384615
2010	21.25
2011	20.5696202531646
2012	19.7568389057751
2013	19.8813056379822
2014	19.6531791907514
2015	18.6813186813187
2016	17.7083333333333
2017	16.953316953317
2018	17.0673076923077
2019	16.7058823529412
2020	16.4319248826291
2021	16.2844036697248
2022	16.1434977578475