My advise would be to ignore it completely. I wasted a lot of time and supplies with recommended percentages. There have been many times when the percentage recommended was 20% but in actuality 5% was the sweet spot for me. The best way to find the correct percentage for you is to make small batches at 5%, 10%, 15%, and 20% and compare them.

The only thing I would use the list for is to find which flavors are VERY STRONG, like M-type and caramel cappuccino. If the recommended percentage is 1% or 2%, you can bet the flavor is strong.

Not my sheet but here ya go. https://docs.google.com/spreadsheet/preview?key=0Av-bhXxhGXredDlMeFU3V1RLbG5reHYzLTV4UzZYMmc

Latest revision is here:

http://www.e-cigarette-forum.com/forum/diy-e-liquid/336110-flavor-apprentice-flavoring-thread-232.html

At least I think it is, it's not officially updated, just by forum members as the thread progresses. It's never a perfectly accurate source but taste is subjective. It's helped me generally figure out a good starting point. If it says something is strong at 5%, I'll know not to just try it at 15% like a lot of others. It's better than nothing when you're starting out.

Yeah I really have to agree with SumDude, I started with the botom of the recommendations and 3-4 days in the juice is still super strong at points. But I like it strong, still not this strong. The next batch I make I will be making a 5% mix and 8% mix. The good thing is that I can always add more flavoring and re-adjust my math to figure out the sweet spot if I go lower.