Should I use "a reduction" or "reductions"?

Please help me to revise this sentence. This technique could provide a reduction of 3%, 2% and 1% for X, Y and Z, respectively. Should I use "a reduction" or "reductions"? Thank you very much.


Since by qualifying your statement with the adverb, 'respectively', you are relating the 3% reduction to X, the 2% reduction to Y, and the 1% reduction to Z, you should use 'a reduction'. In other words, you are performing just one 'operation' on each variable.