Deoxyribonucleic acid in enzyme restriction.

Deoxyribonucleic acid in enzyme restriction. How often would a restriction enzyme such as Not I, which has 8 nucleotides in its recognition sites 5′-GCGGCCGC-3′, cleave DNA on average?

Would it cleave a species’ DNA more or less often if the DNA from that species were 70% A-T rich?