EAR chart, page-21

I assume that NST went after the stock. Looked obvious they were going to 19%. The register can be an open book at times (outside of nominees) for the larger holders and you approach them directly or via a broker. Some guys can actually directly know each other. Its a smaller world when you play in larger numbers.
The 19% would have been several larger sellers and some on market. Only the company really knows.
The end result got them what they wanted to date.