well I guess by now Brita will be in all living CSW`s pedigree(more than once) and the breed started back in 1955, so even that only about 7500 CSW`s are living now, a lot more is dead, which also have Brita in their pedigree(more than once).
If you try counting some of the dogs with small numbers it fits,
But I guess that we must wait for Elf to answer on this ?
Greetings Rolf