Year % of children ages 12-23 months 1980 6.181577696757283 1981 10.789379874818085 1982 11.40699483587965 1983 13.140378386906528 1984 22.63283856638868 1985 28.894978135279928 1986 33.69380153024931 1987 40.36477874926261 1988 44.9122477492914 1989 50.273090622662615 1990 54.25865475553772 1991 47.8452766008824 1992 49.45953732596601 1993 47.07036256194812 1994 49.727659337386186 1995 48.28815131353046 1996 46.20174512198426 1997 44.686770318875865 1998 46.9734378241266 1999 48.062081629174074 2000 50.60296492140524 2001 51.48512988431129 2002 52.83462385635727 2003 55.9944975802117 2004 59.60847883627674 2005 62.204621867246736 2006 63.83852810147536 2007 65.2953820975272 2008 68.99707252272538 2009 72.52907476616011 2010 70.37673551112229 2011 70.4356588911506 2012 69.45135186257873 2013 68.79981362501442 2014 69.69331266509764 2015 69.25038921841296 2016 72.12661249877486 2017 72.76814796515525 2018 75.04765849136791 2019 76.08758882693738 2020 72.78545851804112 2021 71.17442744702154 2022 71.8867350199622