The Discovery 2004-2009 got a four star rating,  while later Discos got 5 stars. I couldn't find an earlier rating. 
BTW the FAQs about the ratings make some very interesting points. For example, a bullbar can cause occupants to suffer greater injuries because it does not crumple to absorb the impact forces. So we are more likely to die if our vehicle has a bullbar. 
Also,  smaller vehiclican be safer than larger vehicles if the smaller vehicle crumples more than the larger vehicle. 
In a crash between a rigid larger vehicle and a smaller vehicle which crumples more,  the occupants of the smaller vehicle may be more likely to survive. 
Interesting. 
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