Hello, I need help turning a dataset into panel data. I am using a dataset from OECD https://stats.oecd.org/Index.aspx?Da...=AIR_EMISSIONS and look only at the observations for Sulphur. Using the comman "duplicates report" I get 1 copy of 90814 observations and 0 surplus. So now I can't turn them into panel data because of duplicates. But if I drop the duplicates only observations from one country remains. What can I do to fix this problem?