Year Jan Feb March April May June July Aug Sept Oct Nov Dec 1989 25.5 25.21 25.62 25.88 27.08 27.32 28.06 28.45 28.3 28.25 27.91 26.9 1990 26.13 25.38 25.45 26.32 27.02 28 28.17 28.71 29.33 29.1 28.34 26.98 1991 25.93 25.92 26.02 26.32 27.45 28.07 28.09 28.6 28.98 28.54 27.83 26.29 1992 25.74 25.72 26.2 26.91 27.19 28.1 28.29 28.51 28.61 29.25 28.1 27.16 1994 25.97 25.94 25.94 26.87 27.73 28.47 28.47 28.65 28.89 28.7 27.94 27.11 1994 26.28 25.77 26.23 26.53 27.44 27.91 27.92 28.36 28.36 28.55 28.13 27.15 1995 26.49 26.37 26.2 26.94 28.24 28.69 29.2 29.24 28.77 28.49 28.01 27.23 1996 26.68 26.08 26.21 26.58 26.88 27.86 27.8 28.53 28.57 28.6 27.75 26.53 1997 26.23 25.62 25.75 26.42 28.3 28.54 28.76 28.94 29.13 28.96 28.32 27.88 1998 27.03 26.7 26.49 27.04 28.34 28.96 29.17 29.65 29.55 29.23 28.52 27.27 1999 26.59 25.56 26.2 27.18 28.36 29.03 28.81 29.52 29.88 29.22 28.51 26.92 2000 25.93 25.66 25.4 26.58 27.7 27.96 28.46 28.71 29.12 29.14 28.31 26.99 2001 26.58 25.97 26.28 27.01 27.65 28.28 28.7 28.83 29.26 28.72 28.15 27.15 2002 26.47 25.91 26.22 26.69 27.38 28.13 28.28 29.07 29.11 29.03 28.5 27.4 2003 26.88 26.51 26.83 27.25 27.8 27.87 28.23 29.07 29.64 29.62 28.64 27.51 2004 26.78 26.53 26.19 27.05 27.32 28.39 28.53 29.16 29.17 29.27 27.83 26.96 2005 25.96 25.32 26.51 28.01 28.57 29.28 29.32 29.83 30.39 29.49 28.68 27.26 2006 26.39 26.15 26.55 27.36 28.15 28.97 28.73 28.73 29.68 29.46 28.72 27.45 2007 26.54 26.67 26.94 27.29 28.31 29.01 28.98 29.02 29.51 29.17 28.21 26.89 2008 26.37 25.66 25.62 26.11 27.45 28.24 28.32 29.1 29.25 28.99 28.22 26.48 2009 26.13 25.79 25.27 26.45 26.95 28.34 28.86 28.91 29.13 29.22 28.76 27.98 2010 27.51 27.43 27.71 27.82 28.59 29.07 29.2 29.82 29.38 29.01 27.94 26.64 2011 26.08 26.15 25.81 26.82 27.36 28.75 28.59 29.06 29.23 29.17 28.4 27.34 2012 26.13 25.98 26.12 26.84 27.35 28.66 28.85 28.91 29.63 29.42 29.02 27.51 2013 26.33 26.08 26.37 26.89 27.62 27.95 28.53 29.12 29.36 29.6 28.56 27.23 2014 26.42 26.23 26.66 27.07 27.64 28.08 28.62 28.78 29.27 29.6 28.7 27.52 2015 26.8 26.94 26.41 27 27.94 28.58 28.4 28.9 29.7 29.8 28.8 27.6 2016 27.1 26.9 26.7 27.4 28 28.7 28.9 nd nd nd nd nd