Facebook Virality Metrics Compared To Open Rates

[KempRugeLawGroup]

I'm trying to put Facebook's Virality Metrics in a framework I understand better. In email marketing, if you consistently get 25% to 30% open rates on newsletters, you're doing solid in most industries. What would you all say the equivalent for that is in Facebook Virality?

Thanks,

Ruben

P.S. If it's drastically higher than 4% - 6%, I'm going to be very sad.