Period	Percent
1970-01-01	1.33
1975-01-01	1.80
1980-01-01	3.60
1985-01-01	10.89
1990-01-01	10.88
1995-01-01	9.94
2000-01-01	9.61
2005-01-01	8.54
2010-01-01	10.71