DB with the largest number of persons
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There are some 7 billion people on Earth.  In my career I worked with DBs that stored data for some 5 million people.  From friends I have heard about Oracle tables with 50-100 million people.  I am curious to hear what is the largest number of persons stored in a single DB THAT YOU HAVE WORKED WITH.  The data should be reliable and clean (e.g. free of duplicates).

FYI, this question occurred to me while studying DICOM.  In DICOM it would be desirable if every living or dead person had a unique universal ID.  In US, with its some 300m people, we often use Social Security Numbers.  How about China, with its >1B people?
DB with the largest number of persons
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I acknowledge that this question may not belong on SO, feel free to recommend another StackExchange site.

There are some 7 billion people on Earth.  In my career I worked with DBs that stored data for some 5 million people.  From friends I have heard about Oracle tables with 50-100 million people.  I am curious to hear what is the largest number of persons stored in a single DB THAT YOU HAVE WORKED WITH.  The data should be reliable and clean (e.g. free of duplicates).

FYI, this question occurred to me while studying DICOM.  In DICOM it would be desirable if every living or dead person had a unique universal ID.  In US, with its some 300m people, we often use Social Security Numbers.  How about China, with its >1B people?