> most coins (no reference, just surmising) are in exchanges rather than wallets owned by the end user.

Are you saying there are 7+ million BTC stored on exchanges? I disagree based on two data points: Bistamp's reserves were 180K in November 2013 and MtGox's were 850K (with 650K of them missing) at the time of its death.

Even if you add BTC-E, Chinese exchanges, Coinbase and LocalBitcoins, it most likely won't exceed 2-3 million which means the remaining 80% is owned by end users directly.