Year	Percent
1990	22.9
1991	23.239
1992	23.685
1993	24.094
1994	24.519
1995	25.327
1996	26.113
1997	26.891
1998	27.376
1999	27.855
2000	28.338
2001	28.81
2002	29.286
2003	29.776
2004	30.289
2005	30.831
2006	31.754
2007	32.7
2008	33.416
2009	33.438
2010	32.486
2011	32.881
2012	33.439
2013	33.332
2014	33.195
2015	33.022
2016	32.789
2017	32.883
2018	32.963
2019	33.034
2020	33.101
2021	33.168
2022	33.231
2023	33.288
2024	33.33
2025	33.353
2026	33.365
2027	33.363
2028	33.359
2029	33.369
2030	33.404