This is the 532nd most frequent Finnish word.
prosentilla
"Prosentilla" means "by percent" or "with a percentage" in English.
Here, 'prosentilla' indicates the specific amount by which the sales percentage grew.
Myynti kasvoi viidellä prosentilla.
The sales increased by five percent.
In this context, 'prosentilla' is used to describe the percent value used to calculate the fee.
Korttiyhtiö perii kolmen prosentin maksun kokonaissummasta.
The card company charges a three percent fee on the total amount.
Here, 'prosentilla' is used to show the percentage increment added to the bonus.