The percentages you see on your PL by Year/Period dashboard all relate to Net Sales.
On your PL by Year/Period Dashboard you will see percentages to the right of the table, and below Gross Profit.
These represent the percentage of Net Sales that that number represents.
Net Sales is defined by tagging your Revenue groups with the Identifier SALES. You would expect to see your Revenue total equal 100% in most cases, as that would be your sales. In the example below, something is off:
Our Income total is 65.2%, and our Cost of Goods Sold shows 34.8%.
The problem here is probably that we have miss identified some of our data. To check for this, go to Settings > Manage groups and look at the Mapping Identifier column:
Here you can see we have accidentally tagged our Cost of Goods Sold group as being SALES. To rectify this just click the pencil icon, and click the blank space at the top of the Mapping Identifier Drop down menu to deselect SALES:
Now if we go back to our dashboard we should see that Income is now 100%.