The proportion of manufacturing using robots in the United States has more than doubled in the past 20 years and the rest of the world has also doubled, replacing certain categories of workers, according to a report released On July 15.

According to research by the St. Louis Federal Reserve Bank, the penetration rate of automation in the United States had risen from 0.5 robots per 1,000 employees 22 years ago to 1.8 by 2017.

The report found that the automobile industry has the highest rate of robot penetration, with France leading the way, followed by the United States and Germany.

Automation has reduced the number of 'middle-skilled' jobs in the middle, but the proportion of high-skilled and low-skilled jobs has increased, the report said.

The study found that France led the way in using robots to build cars, with 148 robots per 1,000 workers, compared with 136 in the United States and about 120 in Italy and Germany.

The study also found that Germany and Italy are ahead of the US in the use of robotics in all manufacturing sectors.