Consider a disk drive with the following specifications. 16 surfaces, 128 tracks / surfaces, 256 sectors / track, 512 B / sector, rotations speed 3600 rpm. The disk is operated in cycle stealing mode whereby whenever one byte word is ready it is sent to memory; similarly, for writing, the disk interface reads a 5 byte word from the memory in each DMA cycle. Memory cycle time is 50microsec. The maximum percentage of time the CPU gets blocked during DMA operation is______?