Contribution of Marx-Engels

The philosophers have only interpreted the world in various ways ; The point is how to change it ?
A Marxist historian of Philosophy could also point out that it was with the beginnings  of the industrial revolution , towards the end of the 18th century that we get the first philosopher who sees knowledge as a product , namely, Kant.
It can seriously be claimed for Karl Marx that his ideas had a greater influence in a shorter time than those of any other i.e., 1848 -[1919 - 1948]. The following table  clarifies the point.
  Political Map of the World in 1919 and 1980
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                                                            1919                                                           1980
                                   ___________________________________________________________
                                             Area                       Population              Area                   Population
                                    in cr km         %              In cfr            %      in cr km    %        in cr.        %
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1. World                       13.58          100            177.7        100       13.58      100      441.5      100
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2. Socialist Countries    2.17             16.0        13.8            7.8       3.56        26.2       146.3     33.1
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3. Others                        11.41           84.00       163.9       92.2        10.02     73.8       295.2     66.9