First off, there is no legal breakdown of how much you should receive (unless one is working for legal minimum wage, which you are certainly not). So what you saw online is a statistical average, from which 3% is not an overly large deviation, especially considering how far outside of the average wage scale you are; per the Bureau of Labor statistics, you make over four times the total private average hourly wage(Source: http://www.bls.gov/news.release/empsit.t19.htm).
As Brick said, "fair" is something you need to define for yourself. Generally, I'd say "are the benefits of being an employee worth the reduction in take home pay ?
Currently, your take home pay is (to be equivalent) less than $111/hour. You have to pay more taxes on it, as brick said above. Since I don't know what state you're in, (and I don't want to do more calculations then necessary), I'll just do federal medicare and social security taxes.
Using Brick's number of 6.2% self-employed tax to cover the above brings us to 111*(100-6.2) - Styx = ~104.12 - stx, where stx is any state taxes that you pay as a contractor that you won't have to as an employee.
This brings your actual take home pay reduction down to (8.08 - stx)/hour reduction in take home pay. So to determine what is "fair", you need to compare the above number to what you are getting from being an employee.
What benefits you recieve is up to you and your employer (and possibly up for negotiation). Some of these have "personal value" rather than a numeric value, and so you have to decide what they are worth to you. Some sample benefits:
-Health insurance: A chunk of free money if you use it. Also, your company may have negotiated a lower price for the insurance than you might be able to get. For example, if I tried to get the medical insurance policy I have through work on my own it would cost me above $300 a month. With my company, it, along with dental and vision insurance, costs me $225.69 a month (and I get a $225 a month health insurance allowance). So, if you're employer's health network/insurance offering is palatable to you, don't just look at the money they give you, see how much it would cost to get an equivalent plan on your own.
-401k matching, etc. (if available): FREE(ish) MONEY!
-(paid) time off: FREE MONEY!
-job security: it is often more difficult for a company to dismiss an employee than a contractor
-possible change to a salaried position/pay schedule: this might be a bonus or a drawback for you.
What these (and possibly other) benefits are worth to you is up to you to decide. Once you find how much that is, divide that monthly amount with the average number of hours you work in a month (or could just decide how much their worth to you per hour you work). Then compare that to 8.08-stx. If it's more, you're coming out ahead. If less, you are losing in this proposition.