What is Erlang written in?

Question

What is Ericsson\'s implementation of Erlang and Erlang/OTP written and compiled in? Is is assembly, C or Erlang itself?

Update 1: Thanks to DrJokepu. If I understan

Answer 1

• 65.9% of erlang code is written in Erlang.
• 13.4% of erlang is written in XML.
• 13.6% of erlang is written in C.
• 1.4% of erlang is written in C++
• ...

You can see a live and update statistics in ohloh site, this report generate from main erlang git repository.