Yesterday Gov. Nathan Deal, House Speaker David Ralston and Lt. Gov. Casey Cagle, have agreed to cut the top state income tax rate to help eliminate the revenue windfall Georgia is expecting from federal tax changes approved by Congress in December. The agreement would cut the top state income tax rate — the rate most Georgians pay on a majority of their income — from 6 percent to 5.75 percent starting next year. The rate would be reduced to 5.5 percent in 2020 if the General Assembly gives its OK, likely during next year’s session. The proposal also doubles the standard deduction for Georgians form $3,000 to $6,000 for married couples filing joint returns.