@crokkon, thanks a lot for yours remarks. For me, the most difficult thing when performing an analysis is when to stop adding variables and correlations!

In the analysis I was interested mainly in the bidirectional flow between STEEM and VESTS considering that the STEEM was already owned, except for the mention I made regarding the purchase of STEEM from blocktrades.

Below I include the monthly evolution of the power-up volume superimposed with the STEEM prices in USD, BTC and ETH as well as the power-up volume valued in those currencies.

Cause or Consequence
(1) Is the price the reason why the demand of STEEM increases or decreases (to convert it into VESTS) or (2) is the price the consequence of the greater or lesser demand of STEEM in a certain currency?

I think that in general terms, there is a combined affect of the two ways of seeing it but mainly I like to interpret the price as the consequence of the demand and for that reason although the price in USD was high during the first months of 2018, the volume of powered-up STEEM was also high.

For cryptocurrencies such as BTC and ETH, prices stabilized since September 2016 which would indicate that demand for STEEM using these crypto currencies remained stable (and low) and therefore the main source of demand for STEEM to convert it into VESTS came from fiat currencies (USD / EUR) in recent times, contrary to what happened at the beginning of STEEM.