It was an unexpectedly stellar year for U.S. stock markets in 2017 – up about 24% thanks to a stronger economy, falling unemployment and expected tax breaks for companies that finally materialized at the last hour . According to Wharton finance professor Jeremy Siegel, since most of the good news has been baked into indexes now, markets will likely take a breather in 2018. The Dow Jones Industrial Average, he projects, will be either flat or will rise by up to 10% by year end, with a correction of 10% or so possible at some point in the year. In this Knowledge at Wharton interview, Siegel also offers his views about the Fed, GDP growth, inflation, wage growth, a Bitcoin bubble and why future Republican economic legislation will face a tough road. An edited transcript of the conversation follows. Knowledge at Wharton: After the Dow went up about 24% in 2017, a lot of people would say there’s just not a lot more room for it to grow.…