Year	Percent
1990	30.683
1991	30.698
1992	30.763
1993	30.916
1994	30.972
1995	31.209
1996	31.475
1997	31.627
1998	31.891
1999	32.248
2000	32.526
2001	32.861
2002	33.207
2003	33.558
2004	33.909
2005	34.255
2006	34.598
2007	34.941
2008	35.284
2009	35.633
2010	35.987
2011	36.345
2012	36.708
2013	37.015
2014	37.315
2015	37.584
2016	37.753
2017	37.902
2018	38.051
2019	38.199
2020	38.346
2021	38.492
2022	38.637
2023	38.781
2024	38.925
2025	39.069
2026	39.213
2027	39.356
2028	39.499
2029	39.641
2030	39.782