(Adds IMF comments)

CARACAS, Nov 22 (Reuters) - Preliminary data compiled by Venezuela’s central bank shows the economy shrank by 16.6 percent in 2017 compared with the year before, two sources familiar with the matter said on Thursday, the country’s sharpest decline on record.

The OPEC nation’s economy has been in free fall following the collapse of oil prices in 2014 and the unraveling of its socialist system, leading millions of people to leave the country to escape hyperinflation and rising malnutrition.

But the central bank has stopped publishing economic indicators amid what President Nicolas Maduro describes as an “economic war” led by businesses and political adversaries.

Preliminary data being prepared by technical experts shows that oil sector activity shrank 11.3 percent in 2017 from 2016 while the non-oil sector contracted 15.2 percent, said the sources, who asked not to be identified.

The International Monetary Fund has been pressuring Venezuela for weeks to provide data on economic activity, consumer prices and balance of payments, the sources said.

The central bank’s board of directors is interested in providing the data to the IMF, according to the sources, but it has not officially approved the figures.

One of the sources said that a member of the board was seeking to “sweeten” the data, or alter statistics such that economic problems look less dramatic.

Venezuela’s Information Ministry and the central bank did not respond to requests for comment.

Jesus Faria of the all-powerful Constituent Assembly this week said that the government had made initial contact with the IMF to provide the data, adding that “we cannot allow ourselves to be hit with IMF sanctions, because such a move could lead to our expulsion from the institution.”

When asked for comment, an IMF spokesman referred Reuters to comments made by IMF Communications Department Director Gerry Rice in a Nov. 15 news briefing, when he said that IMF staff had made contact with Venezuelan authorities on the issue of providing data and hoped the discussions would lead to a “productive conclusion.”

The sources did not provide consumer price data for 2017. But they said that the producer price index, which tends to move in tandem with consumer prices, rose 2,800 percent in 2017 with respect to the prior year.

That is in line with data from the opposition-run legislature, which began calculating economic indicators last year after the central bank stopped publishing official figures.

The legislature says the producer price index rose 2,616 percent last year, and that annual inflation in October topped 833,000 percent. (Additional reporting by Brian Ellsworth Editing by Susan Thomas and Rosalba O’Brien)