<Tr> <Td> </Td> <Td> Canada </Td> <Td> 1,752,910 </Td> <Td> 2017 </Td> </Tr> <Tr> <Td> </Td> <Td> Cuba </Td> <Td> 254,865 </Td> <Td> 2015 </Td> </Tr> <Tr> <Td> 5 </Td> <Td> Dominican Republic </Td> <Td> 174,180 </Td> <Td> 2017 </Td> </Tr> <Tr> <Td> 6 </Td> <Td> Guatemala </Td> <Td> 138,987 </Td> <Td> 2017 </Td> </Tr>

Why do you think there were more trade routes across north america than south america