In the United States, the average public school teacher currently earns an annual salary near $55,202. Reported national average salaries for the last six decades are listed below. Year National Average

Teachers’ Salary
1960 $4,995
1970 $8,626
1980 $15,970
1990 $31,367
2000 $41,807
2010 $55,202
Determine the average salary increase per year between the years 1980 and 1990.

$1,539.70
$8,367.80
$2,566.20
$1,004.10

A is right