As interest in sustainability within MBA programs has increased, so has an interest on assessing their quality and different approaches. "Beyond Grey Pinstripes", a biennial ranking and program survey, published by the Aspen Institute is based on the integration of social, environmental, and ethical stewardship into university curriculum and faculty research. The ranking also weights significantly the extent to which students are exposed to these topics throughout their studies. Participation in the survey requires US-based schools possess accreditation; international schools must also be accredited or be recognized as leading institutions. The 2009-2010 cycle consisted of 149 participating universities. The top-ranked school with a specialization in sustainability, Schulich, is Canadian. 63% of these schools were based in the US, while the remaining 37% were located throughout 24 countries. Although survey information from all participating schools is made available online, the top participating schools were ranked in the "Aspen's Global 100" list. The 2011-2012 survey and ranking again include data from 149 universities.