That information is in the payment schedule appendix to the paid application agreement.
Because it's a contract, it is in iTunes Connect under your agreements. If you haven't agreed to the paid application agreement, you get to read it (and the chart) by requesting the agreement in iTunes Connect.
The exact details are in a series of very long charts, that differ for the various countries, because some countries add taxes to the sale total (like U.S. sales tax) so a 0.99 purchase costs the purchaser 1.06 or something; and in some countries the tax is pre-applied so that the 0.99 purchase costs 0.99 but Apple and the developer split 0.93 (and thus the developer gets proportionally less) because the 0.06 tax comes out of the price.
And naturally rounding is performed according to the chart and whatever accounting laws govern it. If you read "developers get %X" that's a gross simplificatio.