hi - from the following data set example, i would like to return the average of column C if the criteria meets columns A & B. for example. if column A = 7 and column B = 2011, provide the average return of column C. result should be 42.113.... please help. any and all is most appreciated

best regards

8 2011 39.49073466
8 2011 40.10209175
7 2011 41.21885669
7 2011 40.36205606
7 2011 39.45128469
7 2011 41.65746244
7 2011 41.20755325
7 2011 43.41200631
7 2011 44.34023394
7 2011 44.24648197
7 2011 43.49374838
7 2011 44.51996125
7 2011 40.87890875
7 2011 43.80680931
7 2011 42.25107419
7 2011 38.73625294
6 2011 42.39128759
6 2011 42.68405703
6 2011 43.03057088
6 2011 40.92321709