Subsector 221 - Utilities
221111
 Hydroelectric Power Generation 
221112
 Fossil Fuel Power Generation 
221113
 Nuclear Electric Power Generation 
221119
 Other Electric Power Generation 
221121
 Electric Bulk Power Transmission and Control 
221122
 Electric Power Distribution 
221210
 Natural Gas Distribution
221310
 Water Supply and Irrigation Systems
221320
 Sewage Treatment Facilities
221330
 Steam and Air-Conditioning Supply