The popular Latin phrase or expression "Pro rata" meaning "For the rate, proportionately" is so familiar that it has become part of our own language. Examples of the use of the phrase in a sentence are:
"My rate of pay is calculated on a Pro rata basis, I get the same rate of pay as full time colleagues but this is proportional to the numbers of hours I work."
"I received a return premium for my motor insurance which was based on a Pro rata calculation."
"My friend was declared bankrupt and his creditors accepted a Pro rata share of what was owed to them."