Winter winds struck Denmark with force in January. With a wind energy content 224% above normal, the maximum recorded over the past ten years, the country's wind turbines supplied 35.9% of Denmark's electricity over the month, compared with 19% over the whole of the previous year. Wind energy content is measured in a national wind energy index, which in January 2006 was re-booted to account for a long period of relatively low winds since the early 1990s (Windpower Monthly, January 2006). Based on data gathered from a series of reference turbines since 1979, the Danish wind index establishes a statistically "normal" period of wind energy content, expressed at 100%. Deviations from normal are measured from that basis. Accusations that production from Denmark's wind turbines is worthless because electricity in excess of demand is exported at dumping prices have recently been revealed to be false (Windpower Monthly, February 2007).