Africans in New Amsterdam/New York

According to some sources, there were 20,000 or so buried in the African Burial Grounds outside the Wall (Wall Street)1650-1750

Just thinking about normal deaths, thats a lot of people for a city that only had 9,000 around 1674.

Hmmmmmm, that's just not possible, is it? My own estimate, simply based on 'feeling' with New Amsterdam, is that there were about 500 Africans there in the 17th century. Of course, the slave trade intensified once that the English took over New Amsterdam, but I don't think that number can be right. It really doesn't make any sense when we see how slave trade evolved in New Netherland.
It reminds me, Kwame, that we should really do something with the document I wrote. We need to start and have people collaborate on bringing this picture together.
FYI, over the past weekend, I've been able to identify the profiles of key slave traders from Holland - specifically the Coymans family. There were others, but these were very signifDucicant. Given what I understand now, of their importance in 'old' Amsterdam life, there must be records, somewhere.
Another FYI... we're trying to pull people together to work on the Dutch 'golden age', and the Coymans family is in the focus. I hope that, over time, this will unearth new sources regarding the role of some Dutch and the West Indies Company in the trade.

It's such a cognitive dissonance that an era that produced such beauty could also have joined in something so ugly. History is fascinating, isn't it.