Period	Percent
1970-01-01	1.06
1975-01-01	1.31
1980-01-01	1.73
1985-01-01	2.00
1990-01-01	2.14
1995-01-01	2.80
2000-01-01	4.44
2005-01-01	4.85
2010-01-01	5.03