Period	Percent
1970-01-01	5.00
1975-01-01	5.96
1980-01-01	7.74
1985-01-01	10.12
1990-01-01	12.12
1995-01-01	14.13
2000-01-01	17.35
2005-01-01	21.50
2010-01-01	27.65