Period	Percent
1970-01-01	1.20
1975-01-01	1.83
1980-01-01	2.90
1985-01-01	3.06
1990-01-01	3.48
1995-01-01	4.27
2000-01-01	5.48
2005-01-01	7.07
2010-01-01	9.61