I do not know if I can tell you the populations of these three Swedish cities for this year. I do not know if Sweden has done a census recently. However, I can tell you the populations of these cities as given in official literature from the Swedish government. According to the link I am including below, Stockholm is the biggest of these cities. Its population is 1,873,00. The population of Goteborg is 872,000, and the population of Malmo is 599,000. All three of these numbers include suburbs and are clearly approximate populations.
An accurate answer for the population of a country is actually to be assessed on a particular date and time by a process of actual census. It could be done for a prolonged period and then make the updates as on a particular date and time. As you are making a question related to the 2010, you should ensure whether in any of these countries had conducted the census in this year. Other wise you can go for the latest available population and try to estimate the 2010 figure for any particular date time, by any of the methods of forecasting by trends or extrapolation of the time series of populations available for previous years.