All integer division rounds down to the nearest integer. If you need more precision, consider using a multiplier, or store both the numerator and denominator.
(In the future, Solidity will have a fixed-point type, which will make this easier.)
// bad uint x = 5 / 2; // Result is 2, all integer division rounds DOWN to the nearest integer
Using a multiplier prevents rounding down, this multiplier needs to be accounted for when working with x in the future:
// good uint multiplier = 10; uint x = (5 * multiplier) / 2;
Storing the numerator and denominator means you can calculate the result of
// good uint numerator = 5; uint denominator = 2;