Checking spelling and grammar another 2

Hi, I'm not about the grammar and the right words. please see the sentances attached:

On the contrary, decrease in revenues resulted from the asset in Florida in amount of approximately 348 thousands ILS as a result of the Group's improvement programs for the property leading to key renters evacuation in July 2011, and other renters in Q4-2011. The tenants' evacuation towards property improvement led to occupancy decrease from 75.4% in 31 December, 2010 to 60% in 31 December, 2011.


1) the suffix ' in the word tenants' is it OK? the meaning is like renters??
2) Should I write "in amount of" or "in the amount of" ?
3) What's right :"Group's improvement programs" or "Group's enhancement programs""

Best Regards