For a CD, the sampling bars are 16 bits (2 bytes) high. There are 44,000 bars a second, and it's done twice (once for the left stereo channel, and once for the right). So:
2 bytes x 44,000 Hz x 2 = 176,000 bytes per second
x 60 = 10.5 MB per minute,
which is about 780 MB for a 74-minute CD.