Year	Percent
1990	13.46
1991	14.448
1992	15.495
1993	16.604
1994	17.775
1995	19.01
1996	20.245
1997	21.538
1998	22.89
1999	24.301
2000	25.77
2001	26.003
2002	26.238
2003	26.474
2004	26.711
2005	26.95
2006	27.19
2007	25.407
2008	23.702
2009	22.078
2010	20.535
2011	19.074
2012	17.694
2013	16.393
2014	15.17
2015	13.706
2016	13.048
2017	12.758
2018	12.467
2019	12.177
2020	11.886
2021	11.596
2022	11.305
2023	11.015
2024	10.724
2025	10.434
2026	10.143
2027	9.853
2028	9.562
2029	9.272
2030	8.981