Nonfarm payrolls surged by 312,000 in December. Economists surveyed by Dow Jones had been expecting payroll growth of just 176,000. Wages jumped 3.2 percent from a year ago and 0.4 percent over the previous month. The year-over-year increase is tied with October for the best since April 2009. The unemployment rate rose to 3.9 percent as more workers joined the labor force. Here's four experts say that means for markets.