Year	Percent
1990	14.465
1991	14.272
1992	14.269
1993	14.6
1994	15.095
1995	12.864
1996	13.951
1997	15.154
1998	15.435
1999	15.808
2000	16.453
2001	16.354
2002	16.503
2003	17.446
2004	18.442
2005	19.949
2006	21.556
2007	21.659
2008	22.209
2009	23.613
2010	22.845
2011	23.222
2012	23.452
2013	23.694
2014	24.139
2015	25.187
2016	26.066
2017	26.294
2018	26.52
2019	26.738
2020	26.947
2021	27.148
2022	27.341
2023	27.529
2024	27.716
2025	27.906
2026	28.098
2027	28.293
2028	28.49
2029	28.69
2030	28.892