1. A method of compressing an association matrix that contains a plurality of counts that indicate associations among a plurality of pairs of attributes, the method comprising: generating a set of association matrix segments by dividing the association matrix into the set of association matrix segments, a respective one of which defines a subset of the association matrix that includes more than one of the plurality of pairs of attributes, the set of association matrix segments including a first portion of association matrix segments that have at least one count and a second portion of association matrix segments that have zero counts; storing, in an associative memory, identifications of the first portion of association matrix segments so as to identify the association matrix segments that have at least one count; and storing, in the associative memory, the count of at least one of the first portion of association matrix segments that is associated with at least one of the stored identifications as at least one bit plane representation, the at least one bit plane representation identifying a value of the at least one associated count for a bit position of the count that corresponds to the associated bit plane.