Year	Percent
1990	10.543
1991	10.541
1992	10.534
1993	10.524
1994	10.539
1995	10.563
1996	10.577
1997	10.62
1998	10.686
1999	10.748
2000	10.834
2001	10.927
2002	10.89
2003	12.435
2004	14.154
2005	14.623
2006	15.132
2007	15.795
2008	16.522
2009	16.329
2010	15.423
2011	17.31
2012	18.142
2013	18.075
2014	18.968
2015	19.954
2016	20.186
2017	20.487
2018	20.784
2019	21.061
2020	21.306
2021	21.524
2022	21.714
2023	21.882
2024	22.039
2025	22.192
2026	22.342
2027	22.487
2028	22.631
2029	22.778
2030	22.932