Hong Kong remains the world's freest place to do business while the United States has lost its claim to an unrestricted economy, according to an annual report published Wednesday.

Hong Kong, a former British colony which was returned to China in 1997, edged out rival Singapore to claim top spot for the sixteenth consecutive year in the 2010 Index of Economic Freedom.

Australia and New Zealand grabbed third and fourth spot respectively.

The report is compiled by The Heritage Foundation, a conservative Washington-based think tank, and The Wall Street Journal.

Ireland, Switzerland, Canada, the United States, Denmark and Chile rounded out the top ten list, which is based on criteria including economic openness, trade, the efficiency of domestic regulators, and the rule of law.

Mainland China was ranked 140 in the list of 183 countries with Cuba, Zimbabwe and North Korea rounding out the bottom of the list.