Year	Percent
1990	23.965
1991	24.309
1992	24.615
1993	24.918
1994	25.246
1995	25.602
1996	25.882
1997	26.075
1998	26.443
1999	26.715
2000	26.953
2001	26.745
2002	26.618
2003	26.596
2004	26.79
2005	27.597
2006	28.421
2007	29.315
2008	30.235
2009	31.133
2010	31.764
2011	31.854
2012	31.774
2013	31.552
2014	31.387
2015	31.356
2016	31.539
2017	31.639
2018	31.715
2019	31.769
2020	31.801
2021	31.798
2022	31.768
2023	31.711
2024	31.63
2025	31.524
2026	31.417
2027	31.295
2028	31.159
2029	31.006
2030	30.835