The survey of 2,059 people age 18 and over, released Friday, indicated 54 percent approved of organized labor -- 2 percentage points above the 2012 figure but 8 points below the historic average, and 6 points above the all-time low of 48 percent in 2009, Gallup said. Thirty-nine percent said they did not approve of unions.
The all-time high approval was 75 percent in 1953 and 1957. Approval remained above 60 percent until the end of the 1960s, Gallup said.
The survey reveals "a classic partisan" split, Gallup said, with 34 percent of respondents identifying themselves as Republicans indicating approval of unions in contrast with 75 percent of those identifying themselves as Democrats. The South had the lowest opinion of unions, with 47 percent approving.
A majority of respondents -- 52 percent -- said believe unions would become weaker in the future.
"Given that fewer than one in five households [19 percent] have a labor union member, it is perhaps not surprising," that unions are perceived as becoming weaker, Gallup said.
The poll -- which has been taken every year since 1936 -- was conducted Aug. 7-13. The margin of error was 3 percentage points.