hi everyone! im thinking about going into an internal medicine residency-- but i will probably subspecialize after that...

I have a few questions though
1. How many jobs are available throughout the country in the various subspecialties?? (nephrology, allergy/immuno, rheumatology?)
2. What are the fellowships usually like in terms of time committments or research requirements?
3. Which subspecialties are more competitive (obviously GI and cards)?
4. How lucrative are the various subspecialties?
5. Are you wedded to academic medicine forever??

Thanks for all the help!