How much does a system with 9 RX 470 mining cards earn?

[YaBoiSmokey]

Hello, I want to set up a mining system with 9 units of RX 470 8 GB each. It achieves a hash rate of 270 mh/s. By mining ETC at a rate of 270 mh/s, how much gross income can I expect to make per month and how much will the electricity bill be?