Greek Prime Minister Alexis Tsipras has said in an article published by German daily Tagesspiegel.The aim he states is to "refute a widespread myth among German taxpayers" - the one saying "it is they who are paying Greeks' salaries and pensions."Tsipras insists the statement above does not match the truth, though he admits that the country's insurance system has some flaws. In his words, the 2009-2015 Ageing Reports suggest a parallel with German spending on pensions is misleading: in 2007 that expenditure in Greece amounted to 11.7% of GDP in 2007, while in Germany it was 10.4% at the same time. Over the years, Greece's ratio went down to 16.2% in 2013, while Germany's was left unchanged."Simple mathematics is enough to make one see that the increase in pensions expenditures as a percentage of GDP... is owed exclusively to the drop in GDP," Tsipras, a trained engineer, writes.Tsipras added that between 2010-2014, some EUR 13 B had been squeezed out of the insurance system through pension and bonus cuts. "It has to be understood that the system is under pressure in terms of revenues, and not so much in expenditures as it is fen said.""Under conditions of crisis... parents' pensions often finance their children's survival. Pensions of the elderly are the last resort of entire families where no single member is employed, or only one is employed, in a country where unemployment has reached 25% among the population and 50% among young people.""Horizontal cuts" are impossible to blindly implement in this situation, Tsipras argues, but adds Athens is not indifferent to the "imperfectness" of its insurance system and is ready to provide for its "sustainability".He stresses that some agreement has been reached to remove early retirement from the system and to merge insurance funds to save money. In his words, however, the effect cannot be observed immediately or overnight. "[British PM Benjamin] Disraeli said there are three kinds of lies: lies, damned lies, and statistics. Let us not allow the manipulative use of indicators to destroy the mature agreement we have been preparing in the entire period of intense consultations. This is an obligation for all of us," Tsipras concludes. His article comes on a day of a key Eurogroup meeting discussing measures to tackle potentially disastrous consequences of a Greek default and, possibly, an exit from the euro. Athens has been under huge pressure to agree to international lenders' demands for reform, and the pension system has taken a substantial part of the dispute.