"Although no country has ever had within its border an economy in which all markets were absolutely free, the term typically is not used in an absolute sense. Many states which are said to have a market economy have a high level of market freedom, even if it is less than some parts of the population would prefer. Thus, almost all economies in the world today are mixed economies with varying degrees of free market and planned economy traits. For example, in the United States there are more market economy traits than in the Western European countries (an exception being the UK, which is considered, even by Greenspan, to be a freer market than the US)."
http://en.wikipedia.org/wiki/Market_economy#Systems_based_on_a_market_economy