please correct this sentence for me. Thanks very much!?

After 20 years of studies, the Americans have made a conclusion that 90% of individual and corporation who managed their healths have their medical expenses reduced to 10%. On the other hand, the last 10% of individual and corporation who didnt manage their healths have their medical expenses increased to 90%

PS: Im doing my best. Dont flame me

The Americans who studied for twenty years have come to the conclusion that 90% of the individual and the cooperation in which mange the individuals health care was reduced to 10% however the medical expenses of those 10 per cent who did not manage there own health Care raised to a surprising 90 percent

After a twenty year study, the Americans reached the conclusion that 90% of individuals and corporations, that manage their health plans, had their medical expenses reduced by 10%; while on the other hand, the remaining 10%, who didn´t manage their health plans, had their medical expenses increased by 90%.

I hope this is more or less what you were trying to say.

After a 20-year study, it has been concluded that 90 percent of American medical expenses for individuals and corporations that manage their own health plans were reduced by 10 percent as opposed to individuals and corporations that did not manage their own health plans. I DON'T UNDERSTAND. WHAT INCREASED BY 90%?

After a twenty-year study, the Americans made a conclusion that medical expense of ninety percent of the individuals and cooperation that managed their health reduced to ten percent. The medical expenses of the ten percent those who didn’t manage their health increased by ninety percent.

It's called a "run-on sentence" honey. There needs to be some punctuation, as well as some subject (nouns) in there somewhere. As it is, it makes no sense.

I hae no idea of what you're trying say. Write it in short sentences, each with its own idea.

Damm i feel so stupid now