The vast majority of audio we hear these days has undergone lossy compression. Virtually all audio for radio and tv has been through lossy compression, often multiple encode/decode cycles. Recordings are routinely made with musicians in different studios, sending work through digital lines in a lossy format. ALL motion pictures in theaters use lossy compression (Dolby Digital, DTS, etc are lossy codecs). And ya' know what? WE ALL BENEFIT FROM LOSSY COMPRESSION! Bandwidth is a limited commodity. Do we really want satellite radio (or tv) with four channels, or internet radio stations that can only handle two simultaneous streams (listeners)?
Lossy compression is largely benign for a couple of reasons. Yes it's true that compression rates are often as severe as 5:1 or even 10:1. Does that mean that only one fifth of the "information" is recorded? OF COURSE NOT! Not unless the source was WHITE NOISE, because that is the only source which REQUIRES the bandwidth of 16 bit 44.1khz to be transparent.
Linear PCM at 16/44.1 is capable of reproducing sound at EVERY frequency from 0hz to 20khz simultaneously, which lossy codecs can't do. Entirely meaningless, as the above is a description of white noise! MUSIC, on the other hand, has a few dozen (at most) fundamental tones, with harmonically related overtones for a few octaves beyond them...a few hundred discreet tones at any instant...well within the capability of lossy codecs. As well it should be...they are, after all, designed to take into account HOW WE ACTUALLY HEAR...hence the proper term for them "perceptual coding".
People here (and elsewhere) like to rail about how lossy compression damages music. They say this with confidence that there's no way to prove them wrong. Well, I'm about to make 'em quake in their boots, because it is possible to prove OBJECTIVELY exactly what is (or isn't) removed by lossy compression. Rip a cd to your hard deive in linear PCM at 16 bit 44.1khz. Load it into an editor like Adobe Audition. Save the .wav file. Now invert the polarity of the file (both channels) save the same file in mp3 (or another lossy) format (choose at least 192kbps, preferably higher).
In multitrack view, open both the original, unaltered file on one "track", and the compressed/inverted file on another. Time align them (drag them all the way to the left), and hit play. If the tracks are perfectly time aligned, all that will emerge from your speakers is what was removed from the original file by the lossy codec. You may have to crank the speakers VERY LOUD to hear anything at all. What's left will be a whispery, phasey artifact, often not clearly identifiable. Hardly "9/10ths" of the original audio, now is it? Were I to give it an (average guess) score, I'd estimate that perhaps 1/100th, or 1/200th (depending upon codec, bitrate, and complexity of source audio) is actually removed...insignificant when one factors in the well known "masking effect" of human hearing.