Year	Percent
1990	18.011
1991	19.349
1992	21.776
1993	24.639
1994	29.017
1995	30.432
1996	29.273
1997	27.619
1998	27.505
1999	27.086
2000	26.288
2001	25.485
2002	25.66
2003	21.699
2004	18.2
2005	19.132
2006	20.1
2007	20.007
2008	19.914
2009	19.821
2010	18.281
2011	17.055
2012	15.895
2013	14.8
2014	13.88
2015	15
2016	16.9
2017	16.447
2018	15.994
2019	15.541
2020	15.089
2021	14.636
2022	14.183
2023	13.73
2024	13.277
2025	12.824
2026	12.372
2027	11.919
2028	11.466
2029	11.013
2030	10.56