That by itself is a remarkable statistic. The original purpose of non-compete laws was to honor the value of an invention or trade secret and stopping key inventors from directly running away with an invention and thus lowering the incentive for innovation.
But surely not every fifth worker with a high school degree or less in the market is a researcher or crucially involved in the generation of trade secrets. Many people are simply selling their labour, and this data point suggests that non-competes are being abused to an extreme degree simply to chain employees to a business.