<Tr> <Th> Census </Th> <Th> Pop . </Th> <Th> </Th> <Th>% ± </Th> </Tr> <Tr> <Td> 1951 </Td> <Td> 13,549,000 </Td> <Td> </Td> <Td>--</Td> </Tr> <Tr> <Td> 1961 </Td> <Td> 16,904,000 </Td> <Td> </Td> <Td> 24.8% </Td> </Tr> <Tr> <Td> 1971 </Td> <Td> 21,347,000 </Td> <Td> </Td> <Td> 26.3% </Td> </Tr>

Name some spices grown on hills in kerala