I have several shapefiles with the same geographic extend (in my case: Berlin and all its administrative subareas) and statistical (census) attribute data for every subarea displayed trough a choropleth map.
Now I want to show the changing of the figures throughout the given period of time (2007-2015) with QGIS.
Is it possible with several shp or do I have to save all the attribute data for every year into one single shapefile? But if so, how to apply with only one time column (year) but repeating geographical reference (code of subarea) every year then?