The U.S. last year saw the the most heat waves, consisting of abnormally hot weather lasting more than two days, since 1936.
Basically, they admitted that the left was lying to us when saying every year for decades was the hottest ever. The statement above says that for the 80+ years since 1936 there weren't as many heat waves as in 1936.
More than likely caused by putting the NWS thermometers at the city airports...and the heat island effect (pavement/concrete/glass/steel)