Year	Percent
1990	37.733
1991	37.559
1992	37.104
1993	36.645
1994	36.332
1995	36.269
1996	36.244
1997	36.703
1998	36.812
1999	36.861
2000	36.906
2001	36.944
2002	36.97
2003	36.653
2004	36.642
2005	36.673
2006	36.735
2007	36.796
2008	36.833
2009	36.836
2010	36.81
2011	36.808
2012	36.788
2013	36.751
2014	36.631
2015	36.49
2016	36.343
2017	36.346
2018	36.349
2019	36.353
2020	36.356
2021	36.359
2022	36.363
2023	36.366
2024	36.369
2025	36.373
2026	36.376
2027	36.379
2028	36.383
2029	36.386
2030	36.389