Highest Gretna employee salary in year 2018 was $96,337. Gretna employees number in year 2018 was 105. Gretna average salary was $49,917 and median salary was $50,556. According to the last payroll, Gretna average salary is 33 percent lower than USA average but 6 percent higher than Louisiana state average. Gretna employee salaries are usually between $42,287 and $57,470. Top 10% of highest-earning employees have salaries ranging from $66,157 to $96,337. From 2017 to 2018, the average salary of employees at this employer increased 7.0 percent, the median salary increased 8.9 percent.