Moscow, Jun 27 (IANS/RIA Novosti): The Russian Post is among the world's worst postal services, outperformed even by counterparts in countries like Angola, Honduras and Mongolia, says a new study.

The study, titled "Letter Grading Government Efficiency", saw its authors send two letters with wrong addresses and requests to "return to sender if undeliverable" to five biggest cities in 159 countries that have signed various international postal conventions, the Slon.ru website reported Tuesday.

The authors allowed more than 400 days for the letters to return.

However, not a single letter came back from Russia and a number of other countries, including Egypt, Gabon, Myanmar, Somalia, Sudan and Tajikistan, said the study available on Economics.harvard.edu.

The US, from which the letters were sent, predictably topped the list of the fastest and most reliable national postal services, followed by El Salvador and the Czech Republic.

Norway, Canada, Uruguay, Angola, Malawi, Mongolia, Fiji, Congo and Honduras also made the list of countries that returned at least some of the letters within 400-plus days, said the study, which was presented in St. Petersburg.

A postal service's performance correlates with a country's overall development, while usage of non-Latin alphabets further decreases the chances of receiving back a letter with a Latin address on the envelope, the study said.

Russian Post, a state-owned monopoly, increased its profit 65 percent to almost 800 million rubles ($24 million) in 2011.