Stoop, I think a few years ago the Efes Index was a quite good guide to price inflation in Turkey for holidaymakers. Unlike a two-course meal (which could vary between say £7 and £50 in the UK) or an hotel room (2* or 5*, sea view or not?) a 500ml glass of Efes is a pretty standard unit. However, ever since the AKP Government decided to start piling the tax onto alcohol I no longer think it is a reliable guide.
[Some economics used to say that the price of a Big Mac in different countries was one of the most reliable guides to local costs and buying power = standard of living].