Year	Percent
1990	28.86
1991	30.29
1992	31.47
1993	31.87
1994	30.66
1995	29.12
1996	28.75
1997	27.93
1998	28.72
1999	27.4
2000	24.38
2001	24.27
2002	24.28
2003	25.51
2004	24.57
2005	25.49
2006	26.85
2007	27.49
2008	27.79
2009	26.99
2010	33.05
2011	35.42
2012	35.6
2013	35.28
2014	35.92
2015	36.66
2016	38.34
2017	38.521
2018	38.702
2019	38.883
2020	39.064
2021	39.245
2022	39.426
2023	39.607
2024	39.788
2025	39.969
2026	40.15
2027	40.331
2028	40.512
2029	40.693
2030	40.874