Year	Percent
1971	30.82386
1972	29.23511
1973	36.03871
1974	35.03254
1999	69.66716
2000	75.93144
2001	76.76782
2002	78.18305
2003	80.59062
2004	82.35827
2007	89.88634
2008	88.93342
2009	87.43451
2010	88.15792
2017	89.34658