What share of the industrial capacity the country has is being used, in total and for manufacturing alone. The distance from each line’s own long-run average is the read, and the two marks differ: total industry has averaged 79.8% since 1967 and manufacturing 78.6%, so the same reading is more slack on one than the other.
Federal Reserve Board · Federal Reserve G.17 capacity utilisation rates, seasonally adjusted, monthly · percentiles computed here