         keys = _.sortBy _.keys(aggregate), (key) -> key
         mapKeys keys, aggregate
       'total': (aggregate) -> aggregate
+      'period': (aggregate) -> aggregate
+      'gallery': (aggregate) -> aggregate
+      'institution': (aggregate) -> aggregate
 
     aggregateMap[name]? aggregate

    for k, v of aggregations
      aggregations[k] = @prepareAggregate v, k

    aggregations

  prepareAggregate: (aggregate, name) ->

      # sorts the price_range from lowest to highest
      'price_range': (aggregate) ->
        keys = _.sortBy _.keys(aggregate), (key) ->
          [from, to] = key.split('-')
          return 0 if from is "*"
          return parseInt from
