how can I convert the values of a table into percentage values rather than absolute values?
If I'm not mistaken you could do that more or less easily: 

Say for example column comedy. 

The total is 534 (sum). 


132 (1st row) is the 24.71% (132 x 100 / 534). 
3 (2nd Row) is the 0.56%… 
1 is the 0.18% 
398 is the 74.53%.


The sum of 24.71+0.56+0.18+74.53 == 100% (minus rounding, add more decimals for more precision).

So if you add a final ROW with the SUM  (below technology for example) you can cause each cell to perform a Cell * 100 / TOTAL_OF_COLUMN and get your %.

What am I missing?