"Benchmarking by state, region, industry, and group size is critical," Les McPhearson, chief executive officer of UBA, said in a statement. "We see it time and time again, especially with new clients.

An employer benchmarks their rates nationally and they seem at or below average, but once we look at their rates by plan type across multiple carriers and among their neighboring competitors or like-size groups, we find many employers leave a lot on the bargaining table."

Related: Employer health plan costs to rise modestly in 2017

UBA's survey found small-employer costs are lower than average overall, despite the fact that they were "hit the hardest in recent years."

However, even though some cost trends haven't changed much since the Affordable Care Act was put in place, 2016 brought major rate hikes to family plans among these groups, making it harder for small businesses to be family-friendly employers.

Related: 5 employee benefits trends to watch in 2017

Responses from more than 11,000 employers indicate that some things have changed — and surprisingly so. For instance, New Mexico, a state that UBA said was "a low-cost winner in 2015," got bumped from the "best" list in 2016 thanks to a 22 percent increase in monthly premiums for singles and nearly a 30 percent increase in monthly family premiums.

According to the survey, retail and construction employees are the cheapest to cover, with employees in these sectors picking up more of the premium. That means employers are on the hook for even less of already-low costs. "Government employees get the richest and priciest plans," the study said, "but are slowly being asked to pay more of the cost (albeit still far less than what other private-sector employees pay)."

As employers try to contain costs, the survey found that they're adding tiers of coverage — with the percentage of four-tier plans (41.6 percent) surpassing the percent of three-tier plans for the first time.

Ten percent of plans are actually using five-tier plans, and 2 percent use six — and that means that 53.6 percent of plans are offering four tiers or even more. In addition, the past three years have seen the number of 4+ tier plans increase by nearly 80 percent as employers increasingly resort to tiered coverage to keep costs under control.

Related: 7 top workplace benefit trends for 2017

Incidentally, survey results indicated that the lowest-cost monthly group health insurance premiums of all for 2016 were in Washington, D.C., which was not included in the 5 best; its premiums were $279 per month for singles and $708 for families.

And if taken by individual premiums or family premiums alone, the states ranked differently, with some coming in higher up or farther down the list based on solely on family premiums, compared to their standing based on individual premiums or the average of both.

Here are the 5 worst states for health insurance, based on responses to UBA's survey.

5. New Jersey

With a monthly payment of $591 for singles and $1,520 for families, New Jersey came in as the fifth most expensive state — but that $1,520 payment, considered on its own, placed the state 3^rd from the bottom.

4. Vermont

Vermont's singles premium of $607 per month and family premium of $1,397 (the latter of which, on its own, would actually have moved the state up two slots, to 6^th place), make it an expensive place to have coverage.

3. New York

The Empire State is expensive, and its group health insurance no less so. Singles pay $624 a month for their coverage, while families pay $1,572 — and based on the latter alone, New York would actually move down a spot to finish just one up from the bottom.

2. Wyoming

Wyoming had the dubious honor of capturing 2^nd place from the bottom for its singles premiums, while its family coverage alone would have placed it 4^th from the bottom. Monthly premiums for singles and families in the state increased from $534 and $1,326, respectively, in 2015 to $662 and $1,453, respectively, in 2016; that represents nearly a 24 percent increase in single coverage and nearly a 10 percent increase in family coverage.

1. Alaska

If you don't live there, be glad, because singles pay a whopping $780 a month and families $1,714. Both premiums put the state flat-out at the bottom of the barrel.