NASDAQ lists data like this for the short interest in Walmart:
Settlement Date Short Interest Avg Daily Share Volume Days To Cover
4/30/2013 27,988,175 7,442,123 3.760778
4/15/2013 27,609,531 7,570,113 3.647176
3/28/2013 26,370,127 6,788,752 3.884385
3/15/2013 33,099,898 8,217,683 4.027887
What does the settlement date refer to? Does it mean "as of date..."?