From watching my Dad and my own experiences it really seems that actual evictions are quite rare. If you look at the number of years in question and the total number of tenants it would probably work out to around 0.5% to 1% of tenants are evicted. Thats a pretty rough ballpark number though.
The American Housing Survey for 2009 captures reasons people moved and in that data they say that 191,000 people moved in the year because they were evicted. Among the total of 35.3M renters that would equate to about 0.5% of renters being evicted in a given year.
I found an article on SF Gate that said San Francisco logged "1,716 evictions between March 2012 and February 2013". In any case thats in a city of 825k people and 38% of the population rents. That comes out to about a 0.5% eviction rate.
I've got 3 different ways of looking at the eviction rate and come out to about 0.5% each way.
It seems that this is probably a fairly accurate estimate then.
My conclusion : About 0.5% of renters are evicted annually.
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