According to a recent survey,

...if employment-based health benefits were to become taxable, 47% of Americans say they would continue with their current level of coverage, up from 40% in 2012.

Source: "Most Workers Like Current Mix of Wages and Health Benefits, But Discontent Growing," Employee Benefit Research Institute (EBRI), February 18, 2015, http://www.ebri.org/pdf/PR1111.WBS.18Feb15.pdf