GIVING 100 PTS AND BRAINLIEST IF ALL ARE ANSWERED CORRECTLY NOT GUESSED WITH EVIDENCE IF YOU GET THEM ALL CORRECT I WILL THROW IN 200 POINTS

Grandpa ernie is shrinking! over the past 4 years his height decreased by a total of 2.4 cm. it decreased by the same amount each year. what was the change in grandpa ernie's height each year