Year	%
1990	15.3
1995	26.2
1997	27.7
1999	23.6
2001	24.4
2002	23.8
2003	21.7
2004	19.5
2005	19.8
2006	21.7
2007	20.7
2008	20.2
2009	22
2010	21.5
2011	22.7
2012	21.1
2013	19.9
2014	19.8
2015	20.2
2016	19.1
2017	18
2018	18.3
2019	18.6
2020	18.6
2021	17
2022	17.2