...--Fiscal year ended Dec. 31-- 2023 2022 2021 Operational metrics Electric customer accounts 33,556 32,207 33,047 % of electric retail revenues from residential customers 59 57 57 Top 10 electric customers' revenues as % of total electric operating revenue 14 16 15 Service area median household effective buying income as % of U.S. 98 96 100 Weighted average retail electric rate as % of state NA 98 97 Financial metrics Gross revenues ($000s) 108,930 111,937 100,388 Total operating expenses less depreciation and amortization ($000s) 79,319 91,029 73,340 Debt service ($000s) 6,387 6,338 6,253 Debt service coverage (x) 4.6 3.3 4.3 Fixed-charge coverage (x) 2.1 1.7 2.1 Total available liquidity ($000s)* 19,141 24,482 31,130 Days' liquidity 88 98 155 Total on-balance-sheet debt ($000s) 43,023 48,408 52,923 Debt-to-capitalization (%) 14 16 18 *Total available liquidity includes available committed credit line balances, where applicable. Debt service coverage--Revenues minus expenses divided by...