For all rankings of countries research output based on number of publications, citations or most cited publications compared with population, GDP, R&D expenses and other national characteristics the counting method is decisive. Using data freely available the difference between numbers of publications based on Total Counting and Fractional Counting has been quantified. Reduction in numbers of publications going from Total to Fractional Counting ranges from 10 to 45 per cent for different countries. Rankings based on numbers of citations or highly cited papers most likely are even more dependent on the counting method used. Counting methods are in many cases not precisely described or discussed.