CREATE TABLE table_23947 ("City  ( Utility ) " TEXT, "Residential Monthly usage: 1000 kWh" TEXT, "Small power Power demand: 40 kW; Consumption 10 , 000 kWh ,  load factor: 35%." TEXT, "Medium power Power demand: 1 , 000 kW; Consumption: 400 , 000 kWh ,  load factor: 56 %." TEXT, "Large power Power demand: 50 , 000 kW; Consumption: 30 , 600 , 000 kWh ,  load factor: 85%." TEXT)

What is every residential monthly usage if large power demand is 6.86?
SELECT "Residential Monthly usage: 1000 kWh" FROM table_23947 WHERE "Large power Power demand: 50,000 kW; Consumption: 30,600,000 kWh, load factor: 85%." = '6.86'
SELECT "Residential Monthly usage: 1000 kWh" FROM "table_23947" WHERE "Large power Power demand: 50,000 kW; Consumption: 30,600,000 kWh, load factor: 85%." = '6.86'