There were 25 percent more starter homes available in metro Denver at the start of 2017 than at the start of 2016, and about a fifth more trade-up homes, according to a report Tuesday from the real estate firm Trulia. But the inventory in those two categories is so depressed that first-time home buyers or those hoping to avoid a heated bidding award on a more affordable property aren’t likely to see much relief. “Those big percentage increases amount to small nominal increases” Trulia’s chief economist Ralph McLaughlin said.