The offsets match the order of the public final long fields in the GLCapabilities class. For example:
19: glAccum (the first function)
...
719: glGetString
719 - 19 = 700, glGetString's offset
So, when you see a crash at address X, you calculate: X / POINTER_SIZE + 19 and look up the function at that line. The pointer size is 8 on x64, 4 on x86.