<Tr> <Td> </Td> <Td> Iyokan </Td> <Td> 4,677 (6.5%) </Td> </Tr> <Tr> <Td> </Td> <Td> Dekopon </Td> <Td> 3,068 (4.3%) </Td> </Tr> <Tr> <Td> </Td> <Td> Natsumikan </Td> <Td> 2,800 (3.9%) </Td> </Tr> <Tr> <Td> </Td> <Td> Ponkan </Td> <Td> 2,260 (3.2%) </Td> </Tr>

What is the difference between ponkan and orange