That's a typical mp3 data rate.
I don't understand what you're saying here.
Because mp3 doesn't encode in fixed numbers of bits per sample.
CD audio = 44.1k samples/sec * 16 bits/ch * 2 channels. = 1.4112 Mbps
mp3 encoded music is anything typically between 64 and 320 kbps. It's a form of lossy compression.
Graham