Need help with last column and percentage error. Equation for g is a=2x/t^2

Time Interval Average Acceleration Time of Gravity g Distance Trial 1 Trial 2 Trial 3 Trial 4 Trial 5 0.20 m 22sec .20sec 21sec .21sec 20sec 208sec m/sec2 0.40 m 25sec 23sec 24sec 23sec 22sec .234sec m/sec2 0.60 m 29sec .27sec 27sec 28sec 28sec 278sec m/sec2 0.80 m .33sec 32sec 31sec 33sec .32sec 322sec m/sec2 1.00 m 36sec 36sec .35sec 37sec 36sec 36sec m/sec2 Comments: Average: m/sec2 If the accepted value of the acceleration due to gravity is g = 9.81 m/s2, calculate the percentage error of your measured value. accepted value - measured value Percent error = *100% accepted value