Global Conversion stats are meaningless fluff.

Here is what I mean, I looked at some of internal referral stats by referring domain, these are not organic SEO or Type-in referrals, the results were like this:

1. Affiliate A sent 2000 uniques and 1:30 were sales conversions
2. Affiliate B sent 2000 uniques and 1:200 were sales conversions
3. Affiliate C sent 2000 uniques and 1:70,000 were sales conversions

Same sales month similar referral volume

Affiliates with good domains and good traffic make high conversion money.
Affiliates using bulk traffic, volume oriented link trading, traffic generation domains (TGP, MGP, Tubes) have longshot conversion ratios.

It comes down to ROMI (return on marketing investment) or ROE (return on effort [I made that acronym up :P]). Biblically speaking: You reap what you sow -- but you need to be planting in fertile ground too.

I personally experience this with my own personal referral webmaster income -- each webmaster's conversion ratio has differed from 1:120 to 1:1400 on the referral counts but the traffic quality is what affects their respective conversion ratios.

So, global conversion ratios are just bullshit in my experience.