<Tr> <Td> 1952 </Td> <Td> 99,929,000 </Td> <Td> 61,552,000 </Td> <Td> 61.6% </Td> </Tr> <Tr> <Td> 1956 </Td> <Td> 104,515,000 </Td> <Td> 62,027,000 </Td> <Td> 59.3% </Td> </Tr> <Tr> <Td> 1960 </Td> <Td> 109,672,000 </Td> <Td> 68,836,000 </Td> <Td> 62.8% </Td> </Tr> <Tr> <Td> 1964 </Td> <Td> 114,090,000 </Td> <Td> 70,098,000 </Td> <Td> 61.4% </Td> </Tr>

What percentage of the us population voted in the last presidential election