National home prices in January were up 9.7 percent from a year ago, the biggest annual increase since April 2006, according to data aggregator CoreLogic’s home price index.

The index, which tracks repeat sales of single-family homes, rose 0.7 percent in January from December, marking the 11th consecutive month of month-over-month increases.

“Home prices continued to gather steam across a broad swath of the country in January, continuing the positive trend we saw during most of 2012,” said Anand Nallathambi, president and CEO of CoreLogic, in a statement.

“Many states across the western U.S. and along the East Coast saw average price gains of more than 6 percent, which is likely to boost home sale activity into the first half of 2013,” Nallathambi said.

All U.S. states but Delaware (-0.1 percent) and Illinois (-0.4 percent) saw year-over-year increases in January, according to the index.

Arizona (20.1 percent), Nevada (17.4 percent), Idaho (14.9 percent), California (14.1 percent) and Hawaii (14 percent) topped the chart of states with home price increases in January from a year ago.