Sharon Thompson-Schill at the University of Pennsylvania and colleagues did that in the new study.

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The election is still wide open, with the Christian Democrats and Mr Schill's party neck-and-neck with the ruling coalition of Social Democrats and Greens.

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The result, according to Michael Schill and Benjamin Scafidi of New York University, is that 56% of the city's 1.9m rented homes are still regulated.

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