The head of Gwinnett’s county commission is proposing a 2018 budget of roughly $1.67 billion — a figure that’s nearly 9 percent higher than this year. Nearly a third of that increase would be used cover raises and other bumps in compensation and benefits for county employees. The budget proposal presented Tuesday morning by Commission Chairman Charlotte Nash and county CFO Maria Woods would also include funding for 151 new positions throughout the county government. Many of those positions would go to the police and fire departments.