When you look at any AudienceLens tab, you'll see the Composition column beside the Index column. So, what does composition represent?
The composition is the percentage of the selected audience (not the baseline) for that attribute. In the image below, city dwellers represent 26.11% of the chosen audience.
If you hover over the composition figure, you will see the baseline figure, too. In this image, the baseline for city dwellers is 27.95%.
