<Tr> <Td> 1830 </Td> <Td> 157,445 </Td> <Td> </Td> <Td> 185.2% </Td> </Tr> <Tr> <Td> 1840 </Td> <Td> 476,183 </Td> <Td> </Td> <Td> 202.4% </Td> </Tr> <Tr> <Td> 1850 </Td> <Td> 851,470 </Td> <Td> </Td> <Td> 78.8% </Td> </Tr> <Tr> <Td> 1860 </Td> <Td> 1,711,951 </Td> <Td> </Td> <Td> 101.1% </Td> </Tr>

What is the area of illinois in square feet