Bar chart with one column as a percentage of another column

[Anonymous]

I have a table with data like this:

Period     Col1      Col2

201908         5         10

201908         3         12

201908         4           9

201907         8         10

201907         7         13

I want a bar chart that shows Period as the legend.  The first column would be the sum of Col1 for 201908 (5+3+4) divided by the sum of Col2 (10+12+9).  The second column would be the sum of Col 1 for 201907 (8+10) divided by the sum of Col2 for 201907 (7 +13).  If I calculate the percentages by row, it does not return the correct amounts for the graph because it tries to summarize the percentages.  I do not want an average of the percentages.  I am able to get the correct amounts in a table, but I cannot figure out how to translate that into a bar chart.  Please help.