Evictions in Cook County

Is there a reason we can't get a tenant evicted when we placed the Order of Possession with the Cook Sheriff SIX weeks ago? This is the slowest one yet. Can anyone report a good experience with the Cook Sheriff? As a civil attorney, between slow evictions and a nearly 75% failure rate on service of process on Defendants, I don't know what they do effectively. There's a price for one party government I guess.