74.4 GB + 7.56 GB = 81.96 GB (Total memory) >>To get the total memory add the available space and the used space.
(7.56 GB ÷81.96 GB) 100 = % >>To compute the percentage, divide the used space by the total space, and then multiply the result/quotient by 100.
(0.0922) 100 = 9.22%