Millions of Americans lose their health insurance plans every month, by leaving the job through which they got that coverage.

Why it matters: Critics and skeptics of "Medicare for All" worry about eliminating people's existing coverage because most people are relatively satisfied with their employer-based plans. But millions of workers and their families already switch or lose their insurance from their jobs.

By the numbers: More than 66 million Americans voluntarily quit their jobs, were laid off, or otherwise separated from their employers in 2018, and that high turnover rate has continued into 2019, according to data from the Bureau of Labor Statistics.

Details: The BLS data does not measure whether separated jobs offered health insurance.

However, close to half of all private employers provide coverage to their workers, and more than 90% of companies with at least 100 employees offer health benefits.

It's therefore reasonable to estimate at least 2 million workers and their families lose or transfer to new commercial health plans every month.

The bottom line: Behavioral economics teaches that people don't like to lose what they have, a concept known as "loss aversion."

But U.S. workers churn through a dozen jobs in their lifetimes, on average, so people rarely keep their same private health plan over time.

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