Consolidated Statements of Revenue and Expenses Years Ended December 31, 2015 and 2014 ($000 omitted) Increase 2015 2014 (Decrease) Operating Revenue Sales of electricity $ 405,399 $ 460,931 $ (55,532) Lease income — 621 (621) Other 22,960 21,626 1,334 Total operating revenue 428,359 483,178 (54,819 ) Operating and Interest Expenses Purchased power and power production 268,246 321,900 (53,654) Transmission 3,294 4,017 (723) Distribution—operation and maintenance 30,013 29,022 991 Customer accounts, service and information 30,995 28,900 2,095 Administrative and general 38,049 33,220 4,829 Depreciation and amortization 32,506 29,451 3,055 Taxes (property, sales, payroll, etc.) and other 17,342 14,222 3,120 Interest on long-term debt and other interest 19,342 19,412 (70 ) Total operating and interest expenses 439,787 480,144 (40,357 ) Net operating margins (11,428) 3,034 (14,462) Nonoperating income (interest earned, rent, patronage allocations, etc.) 21,029 5,394 15,635 Net margins $ 9,601 $ 8,428 $ 1,173 Street lights: 0.6% $2,425,368 Transmission: 0.8% $3,146,893 Residential: 65.6% $265,841,379 Commercial: 33.0% $133,985,929 Electric Revenue