Small business owner optimism increased slightly in December, according to a monthly survey by the National Federation of Independent Businesses.

The Optimism Index rose 0.5 points to 88 from November’s 87.5, one of the lowest readings in the survey’s history since the 1970’s, according to the NFIB.

The slight uptick in confidence may have been driven by the recent “fiscal cliff” deal reached on New Year’s day, NFIB chief economist William Dunkelberg said in the report.

“The eleventh hour ‘deal’ has brought marginal certainty about tax rates and extenders and will provide some relief to owners, but it certainly doesn’t guarantee a more positive forecast for the economy. The January survey results will be far more enlightening about how the sector views the deal,” he said.

The survey was based on responses of 648 randomly sampled small business members of the NFIB throughout the month of December.

Seventy percent of owners surveyed felt the current period was a bad time to expand, one in four citing political uncertainty as the main reason. Owners cited taxes, regulations, and “poor sales” as the main business problems.

Eight percent of owners felt the current period was a good time to expand facilities — up 2 points from last month. Significantly fewer small business owners expected better business conditions than those who expect decline in the next few months, unchanged from November.

Job creation showed a slight improvement from November, with the average change in employment per firm increasing to 0.03 from -0.04, though 76 percent of owners made no net change in employment.

The NFIB has frequently criticized President Obama’s small business policy, contributing heavily to Republicans and opposing Democrats during the 2012 election cycle, according to research on from the Center for Responsive Politics.

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