"It's not that I'm so smart, it's just that I stay with problems longer." [Albert Einstein]
You need to present percentages of some numbers but they need to sum up to 100% EXACTLY?
Example: You have 115, 222 and 333 but their percentages (rounded to 2 decimals) 17.16%, 33.13% and 49.70% add up to 99.99%, not 100%.
This is how it works - see two examples: one for absolute values, the other for percentages (relative values). This method minimizes the absolute error if you need to amend a value: