tabla.insert(4, 'Paises Euro', tabla['countries']/tabla['Totales'])
 tabla.insert(5, 'Rest of the World',1-tabla['Paises Euro'])
 tabla

           Bad Words    good words  Totales countries   Paises Euro Rest of the World
   jul07    246500.0    16500.0   263000.0  23000.0     0.087452    0.912548
   jul08    7200.0       1200.0     8400.0    500.0     0.059524    0.940476
   jul10    28200.0      3000.0    31200.0   1000.0     0.032051    0.967949
   jul11    258000.0    42000.0   300000.0  19800.0     0.066000    0.934000
   jul12    240000.0    28200.0   268200.0  15600.0     0.058166    0.941834