Small businesses nudged up their hiring during January for a second straight month, according to a survey released Thursday.

The survey by the National Federation of Independent Business showed that the average payroll per company rose by 0.09 workers after rising by 0.03 workers in December. The lobbying group questioned 2,033 of its members for the survey.

The majority of owners surveyed — 80 percent — said they made no changes in their employment levels in recent months. Eleven percent said they had added workers and 9 percent said they had cut their payrolls.

NFIB Chief Economist William Dunkelberg said that the slight improvement, which brought hiring levels back to where they stood in April 2012, was a good sign but that owners remain cautious.

Although Congress agreed to lock in tax rates for 2013 at the start of the year, there are still many uncertainties for small business including the possibility of federal budget cuts. Dunkelberg noted that the government's report Wednesday that the economy shrank at an annual rate of 0.1 percent in the fourth quarter was likely to be discouraging for business owners.

The NFIB survey found that the number of owners planning to create jobs rose 2 percentage points; 3 percent of the owners now say they're planning to hire.

The survey ended on Jan. 28, two days before the fourth-quarter economic report was released.

The NFIB findings came a day after the payroll company ADP said businesses with fewer than 49 employees added a robust 115,000 jobs in January. That brought employment at the smallest businesses to the highest level in six years. The differing results were likely due to the fact that the surveys were based on different groups of small businesses — ADP drew its numbers from payroll data of its clients.

The government releases its report on small business employment on Friday. The Labor Department's figures aren't broken down by company size, but 99 percent of companies in the country are considered small businesses, with fewer than 500 workers. That makes the government report a reliable measure of small business hiring.