While management has been shown to have a greater impact on worker productivity than any environmental factor, environment does matter. In May 2009, a team from CBRE and the University of San Diego's Burnham-Moores Center for Real Estate conducted a survey to examine the impact of green buildings on productivity. All told, 154 buildings containing more than 2,000 tenants -- which were deemed green by virtue of either the Energy Star label or LEED certification at any level -- were surveyed. Forty-four percent of the buildings were located in the central business district, while 56 percent were midtown or suburban. Ninety-four percent of the buildings were multitenant. Most were Class A or A-.