At some point in my career, i was told an anecdote, paraphrased as follows:

Around the turn of the century in Holland, the Dutch government
started collecting mass census data about its citizens.  It began
collecting religion in order to give people a proper burial.  The
intentions were solely good.  In 1939, that data was captured in a
matter of 3 days and (some reasonably high) percentage of the Jews
were executed in a matter of weeks.

I would like to track down a source, preferably a published book,
article or properly referenced news item that confirms/clarifies this
anecdote.  It is quite possible that the reference is to another
European country, but the sentiment is the same - religious data was
captured for good and used for genocide.

Hello.

Yes, the anecdote that you heard is basically confirmed in the
article, "The Dark Side of Numbers: The Role of Population Data
Systems in Human Rights Abuses." Social Research, Summer, 2001, by
William Seltzer, Margo Anderson.

According to the article, the Dutch established a population
registration system for "administrative and statistical purposes," and
then the data from that registration system was used by the Nazis to
apprehend Dutch Jews and Gypsies for deportation to the death camps.

Here is an excerpt from the article:

'In the Netherlands, the effort at establishing a comprehensive
population registration system for administrative and statistical
purposes was completed even before the Nazi-occupation (Methorst,
1936; Thomas, 1937). In 1938 H. W. Methorst, who was then the
director-general of the Dutch Central Bureau of Statistics and
formerly also head of the Dutch office of population registration,
reported on the rapid progress being made in the Netherlands in
implementing a new comprehensive system of population registration
that would follow each person "from cradle to grave" and open "wide
perspectives for simplification of municipal administration and at the
same time social research" (1938: 713-714)...
... These registration systems and the related identity cards played
an important role in the apprehension of Dutch Jews and Gypsies prior
to their eventual deportation to the death camps. Dutch Jews had the
highest death rate (73 percent) of Jews residing in any occupied
western European country--far higher than the death rate among the
Jewish population of Belgium (40 percent) and France (25 percent), for
example."
source:
"The Dark Side of Numbers: The Role of Population Data Systems in
Human Rights Abuses." Social Research, Summer, 2001, by William
Seltzer, Margo Anderson, hosted by findarticles.com:
http://www.findarticles.com/cf_dls/m2267/2_68/77187772/p4/article.jhtml?term=

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search strategy:
dutch census nazis religion
dutch "population registration" religion

I hope this helps.

Wow.  Not only am i impressed with the accuracy and comprehensiveness
of your answer, but with the speed with which you responded.  THANK
YOU

I believe that Napoleon started the ball rolling in The Netherlands,
not for religious persecution (as far as I know) but just so that he
could keep tabs on everyone under his control.