2. The searching apparatus according to claim 1 , wherein said providing unit provides, as said information, an exclusion efficiency indicating a level of exclusion efficiency of data for an individual keyword associated with said searching object data when said keyword is specified as said exclusion keyword.
2. The searching apparatus according to claim 1 , wherein said providing unit provides, as said information, an exclusion efficiency indicating a level of exclusion efficiency of data for an individual keyword associated with said searching object data when said keyword is specified as said exclusion keyword. 3. The searching apparatus according to claim 2 , wherein said exclusion efficiency is calculated, for an individual keyword associated with said searching object data, based on a first parameter indicating a level of exclusion efficiency of data in a set of part of said searching object data when said keyword is specified as said exclusion keyword and a second parameter indicating a level of exclusion efficiency of data in a set of all of said searching object data when said keyword is specified as said exclusion keyword.