About what percentage of employees opt out of employer offered health insurance?

Some would opt out because they were insured under someone else's plan. But some may opt out because they just don't want that health insurance. Do those who opt out get paid more or do they just benefit financially from not having to make the employee contribution?
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employees with kids almost never opt out. those who opt out take home more per month because they're not paying an insurance premium. no one in HR rewards them or anything like that
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