alzheimers disease?

I am doing a report on Alzheimers Disease, and I need to know a few things

1) What percentage of the population has Alzheimers at different ages?
2) What happens inside the brain during the different stages of Alzheimers?
3) How long should a person with each stage of the disease expect to live?

PLEASE INCLUDE YOUR SOURCES!!!! I NEED A BIBLIOGRAPY!!!!