There are 17 values, but only 11 enumeration areas because of some countries have equal values. Divide the number of enumeration areas by the number of segments you want. Three enumeration areas belong in each segment. Start counting from the lowest value. Coloring the Map.
Readability is critical.
Neatness also counts. Color within the lines. A legend is critical to match the sades of the color you have chosen to portray the data on the map with the actual values. The legend should list the data in sequence with the highest value at the top. Look at the map you created.