KIEV, Feb. 17 - Ukraine's GDP declined 20% in January year-on-year, the head of the group of advisors to the chairman of the National Bank of Ukraine, Valeriy Lytvytsky, told Interfax.

"The decline in GDP in January was about 20% according to my reckoning. It's the biggest drop ever. It's a bad start," he said.

The construction sector and industry have been the hardest hit by the economic crisis, he said.