Hi Looking For Answers;
I just rediscovered this post you wrote a while back. Since you began redeeming lawful money in 2013 you have had no tax liability for some time now.
W-4 Form.
Notice the conditions for the Exempt declaration. It sounds as though you meet these conditions since you began your (own) redemption in 2013. You had no tax liability in 2014 which was "last year". And you have no tax liability for 2015 and you will get a full refund of all withholdings.
Enjoy being part of the Run on the Fed.