BRUSSELS, Jan 30 (Reuters) - The euro zone economy expanded at its fastest rate in a decade in 2017, preliminary data showed on Tuesday, and sentiment remained high at the start of 2018 despite a slight dip from a 17-year peak.

The European Union’s statistics office Eurostat estimated gross domestic product in the 19 countries sharing the euro rose 0.6 percent quarter-on-quarter in the last three months of 2017, as expected by economists polled by Reuters, for a 2.7 percent year-on-year gain.

Overall in 2017, euro zone GDP rose 2.5 percent, Eurostat said, the fastest growth rate since a 3.0 percent rise in 2007.

Eurostat also revised upwards growth data for the third quarter to 0.7 percent quarter-on-quarter from the previously reported 0.6 percent and to 2.8 percent year-on-year from 2.6 percent.

Separately, European Commission data showed economic sentiment in the euro zone eased slightly in January to 114.7 from a 17-year high of 115.1 reached in December.

This was a result of a slight decline in sentiment in the retail trade sector, where the mood worsened to 5.0 from 6.0 in December and in services, where it declined to 16.7 from 18.0.

But optimism in industry remained steady at the December new high of 8.8 and consumers were more upbeat at 1.3 points in January against 0.5 in December, signalling the positive trends from late 2017 were continuing. (Reporting By Jan Strupczewski and Philip Blenkinsop)