The above graph represents the 15 years (180 months) beginning on August 1, 1997 and ending July 30, 2011.
Per the latest NOAA/NCDC U.S. temperature data records, the 12-month period ending July was the 5th coldest July-ending period for the last 15 years. In terms of a single month, July 2011 was the 4th warmest since 1895 (July 1936 was the warmest.)
The per century cooling trend of this period, a minus 3.5°F, took place in spite of the huge warmth produced by two large El Niño events during this 15-year span: 1997-1998 and 2009-2010.
For the 10-year period ending July 2011 (August 1, 2001 thru July 30, 2011 – 120 months), the cooling trend accelerates to a very significant minus 12.4°F per century rate – again, per the updated NOAA/NCDC temperature records.
Thanks to Gator for this link