Year	Percent
1990	17.712
1991	17.9
1992	15.153
1993	12.761
1994	10.7
1995	25.9
1996	29.699
1997	33.8
1998	30.1
1999	23.4
2000	29.8
2001	37.4
2002	37.721
2003	38.043
2004	38.365
2005	38.689
2006	39.014
2007	39.34
2008	41.99
2009	41.86
2010	43.45
2011	41.94
2012	42.68
2013	41.17
2014	42.42
2015	41.98
2016	42.267
2017	42.479
2018	42.692
2019	42.904
2020	43.117
2021	43.329
2022	43.542
2023	43.754
2024	43.967
2025	44.179
2026	44.392
2027	44.604
2028	44.817
2029	45.029
2030	45.242