Looking at DO bit query attributes on L.ROOT-SERVERS.NET <http://l.root-servers.net/> publicly available data, DO=1 is around the 130K queries per second, with DO=0 or no DO at around 30K queries per second. I don't agree with "2/3rds don't validate." I will agree that the graph seems stable - others with longer baseline visibility might be able to observe a trend.