When 10 g of benzene (Molar mass = 78 g/mol) reacts with 9 mL of concentrated HNO3(16M) and 9 mL of H2SO4 (18 M), 8.1 g of nitrobenzene (molar mass = 123 g/mol) and 1.2 g of an unknown compound with a high boiling point are obtained.

Calculate the percent yield (%) of nitrobenzene.