Dear
@Nay,
thank you for sharing your question with us. As for your question:
1. I couldnt find official records on this question, however there probably many who can satisfy with the requirements and obtain this Status.
2. The only Statistik I could find is the follwoing from the year 2017( End of the year) you can find under the following link:
https://***.destatis.de/DE/ZahlenFakten/GesellschaftStaat/Bevoelkerung/MigrationIntegration/AuslaendischeBevolkerung/Tabellen/AufenthaltsrechtlicherStatus.html
I believe the one for 2018 will be published end of the year.
I hope I could assist you, if you hvae further questions please do not hesitate to reach out to the community.
Best regards,
Nilab