Eastern Europe, Central Asia and the Caucasus, led by Azerbaijan, made more changes than any other region to make doing business easier over the past year, according to annual rankings of 181 countries by the World Bank.

The bank heralded the 28 countries in these regions for streamlining regulations, boosting property rights and widening access to credit.

Azerbaijan jumped 64 spots from last year to 33 by cutting bureaucratic delays to start a business and sell property, making employment laws more flexible and simplifying tax payment. Albania, Kyrgyzstan and Belarus were other top reformers, the bank said.

"In the beginning, it was Eastern Europe that was reforming. All of a sudden, this year we've seen this move toward the east and Azerbaijan," said Sylvia Solf, who managed the report. "There is a lot of competition now in that region."

For the third year in a row, the bank ranked Singapore as the easiest country to do business, followed by New Zealand and the U.S. The top eight countries — including Hong Kong, Denmark, United Kingdom, Ireland and Canada — were unchanged from the previous report.

The bank ranks economies based on ten indicators that measure the time and cost of government requirements in starting, operating and closing a business, trading across borders and paying taxes. The rankings don't reflect macroeconomic policy, infrastructure, currency volatility, investor perceptions or crime rates.

Large economies that fell in the rankings include Germany, which dropped to 25 from 20, Mexico, to 56 from 42, and Russia, to 120 from 112.

"Economies need rules that are efficient, easy to use, and accessible to all," Michael Klein, a World Bank vice president, said in a statement. "Otherwise, businesses get trapped in the unregulated, informal economy."

Venezuela was the lowest-ranked Latin American country at 174 and the only country in the bottom ten not in Africa, the bank said. Venezuelan companies must pay more than 50 taxes during the year, Solf said.

"Venezuela is one of the few countries that made things more complicated with more bureaucracy," Solf said. "It's an interesting trend and it makes you wonder why."