At most companies, employee health insurance premiums vary only by family size and type of plan. At a small percentage of firms, however, another variable is taken into account: salary. At these companies, workers' premiums are pegged to how much they earn. Workers who earn less, pay less. Now, as employers look toward 2014 ? when companies that don't offer affordable coverage to their workers may begin to face penalties ? experts say more are considering this strategy. General Electric adopted this salary-based premium model more than 20 years ago.