On the eve of the referendum that decides whether the U.K. stays in the European Union, Christie's had its smallest tally for a major evening sale of Impressionist and modern art in more than a decade.

The sale total came to 25.6 million pounds ($37.8 million), well below its presale estimate of 32.8 million pounds to 48.7 million pounds. Twelve of the 33 offered works failed to sell, including a subtle landscape of 1872 by Claude Monet that carried a guarantee for the seller. It was expected to bring between 4.5 million pounds to 6.5 million pounds.

The evening’s total was a 64 percent decline from a year ago. Christie's London series will later include a themed auction with star lots to commemorate the company’s 250th anniversary on June 30.