One of objections that opponents of Obamacare give against the landmark health care legislation is that employers will have an incentive to drop the health insurance coverage that millions of workers currently receive as employee benefits. Yet even before Obamacare became law, the trend among employers was to offer health insurance to fewer employees, leading to increased stress on families seeking to protect themselves against potentially catastrophic health care costs.

In particular, a recent study from the Employee Benefit Research Institute looked at the question of workplace-provided health insurance coverage. With its examination of trends in recent years, the EBRI confirmed what has long been a known fact: that the cost of health insurance is the key determining factor in whether employees choose coverage. Let's take a closer look at the study and its implications for your insurance coverage going forward.

2 key trends in health insurance
The EBRI study focused on two different measures of health insurance coverage. First, the study looked at the percentage of workers with employer-provided health benefits. Then, it turned to the reasons that those who weren't covered cited in explaining why they went without insurance coverage.

On the first topic, trends toward a smaller percentage of workers having employer-based health benefits have been in place for well over a decade. After peaking above 80% in 1999 and 2000, the percentage of people having any employer-based source of insurance coverage -- whether in their own name or by being a qualifying dependent on another person's policy -- has fallen steadily ever since, with levels declining to the low 70% range as of early last year. In particular, coverage in workers' own names has fallen dramatically in recent years, with the 60.4% in December 2007 falling to just 54.7% as of October 2011.

Those figures suggest that more employers have been pulling back on offering health insurance benefits to their workers. Yet in the second part of the survey, the experience of uninsured workers strongly contradicts that hypothesis, pointing instead to cost considerations as being paramount in the decision to go uncovered.

In particular, the EBRI found that as recently as 2001, roughly 40% of uninsured workers claimed that their employers didn't offer them health benefits. Yet by the end of 2011, that figure had declined almost in half, to 22%.

Access therefore might not be the issue. But what nearly 90% of uninsured workers say is that even if they're eligible for employer-provided health insurance, its cost is too high for them to accept it. Cost has always been a major consideration for those who go uninsured, with figures since 1995 routinely falling within the 70% to 90% range, but cost has been particularly important in the years since the 2008 recession.

Why the uninsured are so important
One big question that Obamacare proponents and opponents are wrestling with right now is the extent to which these uninsured workers will get coverage under new health care laws. On one hand, the individual mandate requires most people to obtain coverage. Yet if cost truly is the problem, Obamacare provides an exception to the mandate that exempts those for whom the cost of care is prohibitive.

That in turn could create a problem for hospital companies. Tenet Healthcare (NYSE:THC), Community Health Systems (NYSE:CYH), and Health Management Associates (NYSE:HMA) have all seen their share prices jump sharply as investors grow increasingly excited about the prospects of uninsured Americans getting mandated coverage under Obamacare. The hope is that by having more people insured, these hospital companies will lose less in uncovered health care expenses they incur when they treat uninsured patients.

As a result, much will depend on government subsidies to help low-income workers bridge the gap between available coverage and affordable coverage. If subsidies don't succeed, then the real crisis in employer-provided health insurance could well continue -- and hospital stocks could give back much of their gains.

Tune in every Monday and Wednesday for Dan's columns on retirement, investing, and personal finance. You can follow him on Twitter @DanCaplinger.

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