I just did an estimate of the "Bitcoin National Debt" (BND), which is the minimum amount that the bitcoin system "owes" to the people who are holding bitcoins. It is between 483 million and 17.2 billion USD.
For example, someone who bought 10 BTC a year ago must have paid close to 600 $/Ƀ, the market price at that time. Therefore, he must be expecting to get at least 6600 $ if he were to sell or spend those bitcoins -- the 6000 $ that he invested, plus 10%/year of return. By doing that math for every bitcoin and adding the results we would get the BND.
Unfortunately, there is no way of knowing when any given lump of bitcoin was bought by its current owner. The purchase may not even have been recorded in the blockchain (e.g. if it was bought in an exchange and left there). We can only assume that the last purchase of a bitcoin that was mined on day X will (almost) surely have occurred on date X or after that. Therefore, by looking at the minimum and maximum price in that interval, we can get uper and lower bounds to the expectations of its owner.
For example, the 25 bitcoins that were mined on 2014-04-01 (when the price was ~450) may have been bought by their present owner(s) on 2014-06-01 (when the price was at its highest, ~680) or on 2015-01-14 (when the price was at its lowest, ~150). So, the current owners of those bitcoins, even if they are happy with a 10%/year return on investment, now expect to get from them between 25 × 150 $ and 25 × 680 $ plus the 10%/year.
I may post more details later if I get the time.
Too many variables to draw reliable conclusions concerning cause and effect, but could make for interesting data points in themselves.
"National debt" is wrong, even with tongue firmly in cheek, a debt is a promise to repay... which bitcoin doesn't promise. The exchange rate volatility risk is foisted upon current owners and traders (not rights to future labor and income), and rightly so.
Maybe "bagholder pain index" or BPI can be produced, at least partially, with this data.
