I felt IM was 60%
Surgery was hard to say. Questions which involved the a surgical treatment as the answer was proably around 10%, but I felt IM and Surgery questions on diagnosis/prognosis/principles overlapped quite a bit.
Psych was 10%
Pediatrics was 10%, but some of the hardest zebras came from pediatrics.
OBGYN was 10%
Keep in mind 10% would be ~34 questions