Year % of children ages 12-23 months 1980 6.250635948257536 1981 12.063138580574128 1982 13.93491744603501 1983 20.852669036086574 1984 25.874895409895927 1985 32.56085771251169 1986 39.43813789605805 1987 43.79954250203286 1988 48.567430993009786 1989 55.13353984002081 1990 56.682066498951585 1991 53.40629828142182 1992 50.24870988769978 1993 51.07339823014497 1994 54.424671115741994 1995 54.035392325744674 1996 53.70499073237936 1997 53.2918434862785 1998 51.578157201510976 1999 49.8168177943297 2000 52.28558859053139 2001 52.46530559016248 2002 53.666871855422606 2003 56.2004572848231 2004 58.26680156227372 2005 60.09880645930912 2006 62.749225562662026 2007 64.63616787068726 2008 67.13652158644672 2009 71.28865993049769 2010 71.49546881072663 2011 70.08002493534474 2012 70.13251155203201 2013 69.06452063633873 2014 68.96033616728997 2015 68.15895838897225 2016 68.33461810321627 2017 69.89858576326816 2018 70.14542057581218 2019 71.04529717780458 2020 69.98253592449292 2021 68.27777437646363 2022 68.64476685604485