Around 189,000 people were informers the secret police of the GDR's communist regime, when the Berlin Wall fell in 1989 -- that's according to Thuringia's state office for researching East Germany's Stasi on Monday, March 10.

Previously, the number of Stasi informers in 1989 had been estimated at 174,000. The complete report, by historian Helmut Mueller-Enberg, is to be published on Thursday.

The Stasi relied heavily on ordinary people to report activity that deviated from the official political ideology in the country of 16 million. According to Mueller-Enberg, 620,000 people worked undercover for the Stasi in both East and West Germany during the 51 years of the communist state's existence.

Around 12,000 of them were West Germans. In East Germany, one in 20 communist party members was a Stasi spy.

According to the report, political ideals served as the primary motivation for people to turn in their neighbors, friends and acquaintances to the secret police. Financial incentives played only a minor role and blackmail was rare.