A new study is proving the auto industry is the driving force behind high concentrations of robots.

While there are incidences of robots throughout the U.S., concentrations have been found to be significantly higher in the areas of Michigan and Ohio, both of which are major manufacturing regions for the auto industry, Axios reports.

Particularly dense concentrations have been found in the industrial upper Midwest, Northeast and Upper South, in addition to San Francisco and Los Angeles, with approximately half of the robots working as welders, painters and in product assembly and packaging, Brookings reports.

The auto industry houses almost half of the industrial robot population in the country with about 233,305 in total working in the sector. Detroit leads all U.S. cities with about 15,000 robots in place, nearly five times more than any other major market.