Period	Percent
1970-01-01	0.10
1975-01-01	0.20
1980-01-01	0.30
1985-01-01	0.40
1990-01-01	0.51
1995-01-01	2.24
2000-01-01	4.81
2005-01-01	3.41
2010-01-01	2.96