Working on taxes takes up a lot of time, and a study done by the National Small Business Association shows that small business owners are spending more and more time on it, as tax law becomes more complex and changes come more frequently.

The study, which surveyed small businesses across the country, concluded that two-thirds of small businesses spent more than 40 hours on federal taxes last year. This number is 7% greater than last year’s time spent.

Most business owners surveyed said that the administrative burden of time spent on taxes is more of a challenge than the amount of tax owed. It’s complicated and time-consuming, and most small business owners become frustrated with the process.

As expected, the majority of the owners surveyed said that they support reforming the tax code. Seventy-three percent favored reducing corporate and individual tax rates and deductions, and 53% supported a solution similar to the “fair tax,” which would replace all income and corporate taxes with a national sales tax.