As commercial developers ramp up their construction pipelines, some markets are seeing more building cranes than others. Real estate services firm Colliers International has just released its 2015 North America Office Market report, where its researchers note that office construction activity is concentrated primarily in the top few markets around the country. According to the report, “The top 10 markets accounted for 66.2 million sq. ft., or 58 percent, of the 113.8 million sq. ft. of office space under way in the U.S. and Canada in first quarter 2015, more than double these markets’ 27 percent share of existing office inventory.” To see which U.S. metros saw the greatest volumes of new office construction in the first quarter, click through our slideshow.