Year	Percent
1990	48.528
1991	48.475
1992	48.426
1993	48.386
1994	48.365
1995	48.413
1996	48.442
1997	48.449
1998	48.477
1999	48.436
2000	48.408
2001	48.388
2002	48.372
2003	48.357
2004	48.339
2005	48.315
2006	48.291
2007	48.265
2008	48.236
2009	48.203
2010	48.166
2011	48.124
2012	48.086
2013	48.055
2014	48.038
2015	48.041
2016	48.053
2017	48.107
2018	48.173
2019	48.25
2020	48.336
2021	48.422
2022	48.517
2023	48.617
2024	48.716
2025	48.811
2026	48.893
2027	48.972
2028	49.048
2029	49.122
2030	49.195