Year	Percent
1990	22.969
1991	23.498
1992	24.154
1993	24.67
1994	25.137
1995	25.595
1996	23.318
1997	21.221
1998	19.297
1999	21.185
2000	23.437
2001	22.972
2002	22.509
2003	22.052
2004	20.928
2005	19.86
2006	18.857
2007	18.049
2008	19.053
2009	17.45
2010	17.777
2011	17.536
2012	17.347
2013	17.169
2014	16.999
2015	16.821
2016	17.099
2017	16.919
2018	16.743
2019	16.572
2020	16.409
2021	16.285
2022	16.156
2023	16.018
2024	15.869
2025	15.706
2026	15.539
2027	15.365
2028	15.187
2029	15.01
2030	14.835