Russia's economy shrank by 3.7 percent in 2015 as the country struggled with the low oil price and international sanctions.

The state statistics service says in a preliminary report Monday that last year also saw a 10 percent drop in retail sales and a one-third drop in foreign trade.

With Russian government revenues hurt by the fall in the oil price, the government has said it will have to make cuts to the budget for 2016, which was adopted in October and based on an oil price of $50 per barrel. Brent crude oil traded slightly above $31 a barrel on Monday.

The ruble weakened slightly to around 79 against the dollar in Monday trading, remaining below the record of almost 86 set Thursday.