What percentage of Bitcoins stored in a multi sign address? I am looking for a statistic of the usage of multi-sig addresses over time.
More concrete: what is the percentage of Bitcoins stored in a multi-sig address over time.
I calculated it here summarized per month:

  month       btc      count
  201201   0.010000      1 
  201202   1.150000      5 
  201203   0.015000      2 

  201209   0.010000      1 

  201212 137.737103     46 
  201301   9.781411      9 
  201302   0.100000      2 
  201303 527.570925    724 
  201304 385.334698   1137 
  201305 300.712263    991 
  201306  20.247942     78 
  201307   6.251700     13 
  201308   0.934915      2 
  201309   0.499281     10 
  201310   0.233557     45 
  201311   0.903894    352 
  201312   0.184625    796 
  201401   0.187421   1237 
  201402   0.546214   4086 
  201403   0.573631   4314 
  201404   1.406338  12761 
  201405   1.019459   9331 
  201406  13.324859  11959 


I counted all multisig output transactions with valid public keys.