Year	Percent
1990	27.011
1991	27.03
1992	27.218
1993	27.474
1994	28.678
1995	26.749
1996	25.746
1997	24.754
1998	23.788
1999	23.782
2000	25.046
2001	26.446
2002	22.203
2003	23.096
2004	24.03
2005	24.994
2006	25.991
2007	29.135
2008	28.607
2009	28.11
2010	28.683
2011	28.443
2012	28.904
2013	29.672
2014	28.536
2015	27.429
2016	27.255
2017	27.57
2018	27.879
2019	28.188
2020	28.499
2021	28.815
2022	29.133
2023	29.456
2024	29.788
2025	30.131
2026	30.489
2027	30.859
2028	31.241
2029	31.629
2030	32.021