year mo data-type region extent area 1979 9 Goddard N 7.05 4.58 1980 9 Goddard N 7.67 4.87 1981 9 Goddard N 7.14 4.44 1982 9 Goddard N 7.3 4.43 1983 9 Goddard N 7.39 4.7 1984 9 Goddard N 6.81 4.11 1985 9 Goddard N 6.7 4.23 1986 9 Goddard N 7.41 4.72 1987 9 Goddard N 7.28 5.64 1988 9 Goddard N 7.37 5.36 1989 9 Goddard N 7.01 4.86 1990 9 Goddard N 6.14 4.55 1991 9 Goddard N 6.47 4.51 1992 9 Goddard N 7.47 5.43 1993 9 Goddard N 6.4 4.58 1994 9 Goddard N 7.14 5.13 1995 9 Goddard N 6.08 4.43 1996 9 Goddard N 7.58 5.62 1997 9 Goddard N 6.69 4.89 1998 9 Goddard N 6.54 4.3 1999 9 Goddard N 6.12 4.29 2000 9 Goddard N 6.25 4.35 2001 9 Goddard N 6.73 4.59 2002 9 Goddard N 5.83 4.03 2003 9 Goddard N 6.12 4.05 2004 9 Goddard N 5.98 4.39 2005 9 Goddard N 5.5 4.07 2006 9 Goddard N 5.86 4.01 2007 9 Goddard N 4.27 2.82 2008 9 Goddard N 4.69 3.26 2009 9 Goddard N 5.26 3.76 2010 9 Goddard N 4.87 3.34 2011 9 Goddard N 4.56 3.21 2012 9 Goddard N 3.57 2.41 2013 9 Goddard N 5.21 3.78 2014 9 Goddard N 5.22 3.74 2015 9 Goddard N 4.62 3.42 2016 9 Goddard N 4.53 2.91 2017 9 Goddard N 4.82 3.35 2018 9 Goddard N 4.79 3.35 2019 9 NRTSI-G N 4.32 3.13