songs. There were no DJs. On December 6, 1976, CKVL-FM became CKOI-FM, and the station's format was changed to progressive rock, with a full-time DJ staff. It evolved into a largely new wave-based format in 1979 and moved to a rock-leaning Top 40/CHR format in 1980. The fall 1991 Bureau of Broadcast Measurement ratings were a defining moment for the station, as it found itself in first place in Montreal with over a million listeners in full coverage. It was the first time that an FM station finished in first place in the fall ratings, which are the most important for the radio industry as they are used to determine prices charged for advertising. CKOI-FM would have over a million listeners in 32 consecutive books (excluding summer ratings starting in 2001, which were only compiled for the central area of the market), from fall 1991 to fall 2002 inclusively. (The station had already managed to get a million listeners on a few occasions during summer ratings before 1991.) The station's best-ever results under the old diary system were obtained in the spring 1995 ratings, in which CKOI-FM registered 1,341,300 listeners. By comparison, CKAC, which had been Montreal's usual #1 station, had 775,500 listeners. CKOI-FM, along with sister station CKVL, was sold in 1992 by its founder Jack Tietolman to Metromedia CMR, a company owned by Pierre Arcand and Pierre Béland. Both stations would be sold again in 2001, this time to Corus Entertainment. On January 1, 2002, the station's city of licence became Montreal. Until then, it had officially been Verdun; however, as a result of a forced municipal merger, the city of Verdun became a borough of Montreal. CKOI-FM long had the highest power output of any radio station in Canada, and the second highest power in North America, only exceeded by WBCT in Grand Rapids, Michigan, which operates at 320,000 watts. Unlike other North American superpower FM stations that have lowered their power since the 1990s, CKOI-FM actively protected its 307,000-watt signal. For instance, when Industry Canada advised the station in 2004 that it was out of compliance with updated Code 6 safety regulations (which deal with acceptable levels of radiation), owner Corus Entertainment invested in emission reduction equipment instead of simply reducing power, which would have restricted output to 122,800 watts. The station's studios were moved for the first time in July 2006, after decades at 211