Year,Cumulative savings
1978,0
1979,0.002
1980,0.007
1981,0.015
1982,0.035
1983,0.064
1984,0.08
1985,0.092
1986,0.104
1987,0.114
1988,0.116
1989,0.126
1990,0.136
1991,0.155
1992,0.193
1993,0.258
1994,0.333
1995,0.413
1996,0.484
1997,0.526
1998,0.59
1999,0.651
2000,0.738
2001,0.992
2002,1.222
2003,1.318
2004,1.422
2005,1.575
2006,1.759
2007,2.02
2008,2.314
2009,2.583
2010,2.771
2011,3.037
2012,3.279
2013,3.569
2014,3.831
2015,3.8
2016,3.88
2017,4.18
2018,4.44