The upfront market is moving more slowly than broadcasters anticipated as advertisers resist efforts to panic them into paying high prices. But NBC and CBS have made some deals with low-double digit percentage increases in unit rates vs last year, industry sources say.

There’s no word yet on other key details that will affect the final tally, including how much inventory is being sold and what ratings the networks are guaranteeing.

Still, NBCUniversal CEO Steve Burke told an investor group this week that NBCU’s seeing “very strong” upfront sales with its effort “more than half way done.”

That apparently includes ad sales for NBCU’s cable channels as well as NBC, and previously written multi-year deals. Broadcast prime time and cable prices are up by low teen percentages for each viewer reached, we’re told.

CBS also has begun to sign some deals with low-double digit percentage price increases.

With industry-wide ratings falling, Wall Street analysts expect all broadcasters to see a mid-single digit increase in the total dollars they’ll collect in this year’s upfront market.

MoffettNathanson Research’s Michael Nathanson said yesterday that the industry is benefiting from “ratings normalization and a spot advertising market that has caught fire” following “two years of really weak viewership, scatter pricing and low upfront volumes.”

Others have also noted that networks will fare well due to economic stability, plus developments driving specific industries to buy ads. Pharmaceutical companies are increasing their budgets before patents expire on several blockbuster drugs. Auto makers and telecom providers are angling to increase market share. Hollywood studios need to promote the growing number of big-budget releases. And consumer products companies including Procter & Gamble have become disenchanted with some digital media.