Start by dividing 1 billion coins between 72. Now take an average trading volume for the last 2+ years. Assume a % corresponding to dumping -- quite relentless. Be generous to cover for probable +/-. Then substract. The figure you come up with from the result of billion/72. It's really quite simple. Not exact but... illuminating.
Another illuminating FACT: Assuming Damelon's holdings in nxt were worth (unrealized) 1,000 btc prior to the announcement. It will be worth now 7,000 btc (some of them, quite a few, realized at much higher value too) ain't life great... for Damelon et all? No wonder he feels "generous" to get sheep to maintain the network...
Ah the magic of basic, simple math mixed with a bit of critical thinking!
Did you first imply he has 13 000 000 coins and then say it's worth 7000 BTC?
I see here it's worth 157 BTC - market price, disregarding the liquidity