Year	%
1999	29.6
2001	29.1
2002	29
2003	28.2
2004	31.7
2005	30.8
2006	24.5
2007	25.1
2008	23.7
2009	22.9
2010	25
2011	24
2012	24.5
2013	24.7
2014	25.7
2015	26.7
2016	25.3
2017	28.4
2018	29.2
2019	25.2
2020	21.5
2021	23.6
2022	23