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