average voip compression rates?

I am running some tests on audio compression and trying out Skype's Silk. In their test application I am seeing compression rates of 94%. This see开发者_运维知识库ms high, is this a typical rate on Silk? Is this comparable to other audio compression codecs?

Most speech/telephony codecs run at pretty low bit rates, so 94% does not sound unrealistic, particularly if you're starting with a fairly high sample rate. E.g. 22 kHz 8 bit audio compressed to a 9600 bps stream would be around 94% compression.