Year	Percent
1990	19.04
1991	19.213
1992	19.368
1993	19.507
1994	19.651
1995	19.818
1996	19.913
1997	20.022
1998	20.18
1999	20.337
2000	20.481
2001	20.25
2002	20.095
2003	20.018
2004	20.035
2005	20.365
2006	20.785
2007	21.251
2008	21.633
2009	22.014
2010	22.305
2011	22.511
2012	22.637
2013	22.695
2014	22.751
2015	22.855
2016	23.034
2017	23.158
2018	23.263
2019	23.351
2020	23.425
2021	23.478
2022	23.515
2023	23.526
2024	23.499
2025	23.424
2026	23.321
2027	23.174
2028	22.991
2029	22.787
2030	22.572