<Tr> <Td> C+ </Td> <Td> 77% - 79% </Td> <Td> 2.33 / 4.00 </Td> </Tr> <Tr> <Td> </Td> <Td> 73% - 76% </Td> <Td> 2.00 / 4.00 </Td> </Tr> <Tr> <Td> C - </Td> <Td> 70% - 72% </Td> <Td> 1.67 / 4.00 </Td> </Tr> <Tr> <Td> D+ </Td> <Td> 67% - 69% </Td> <Td> 1.33 / 4.00 </Td> </Tr>

What is the grading system in the us