<Table> <Tr> <Th_colspan="2"> Holden Caulfield </Th> </Tr> <Tr> <Td_colspan="2"> An interpretation of Holden Caulfield on the cover of the 2012 book The Catcher in the Rye and Philosophy by Heather Salter and Keith Dromm . </Td> </Tr> <Tr> <Th> First appearance </Th> <Td> "I'm Crazy" </Td> </Tr> <Tr> <Th> Last appearance </Th> <Td> The Catcher in the Rye </Td> </Tr> <Tr> <Th> Created by </Th> <Td> J.D. Salinger </Td> </Tr> <Tr> <Th_colspan="2"> Information </Th> </Tr> <Tr> <Th> Gender </Th> <Td> Male </Td> </Tr> <Tr> <Th> Occupation </Th> <Td> Student </Td> </Tr> <Tr> <Th> Family </Th> <Td> D.B. Caulfield (brother) Phoebe Caulfield (sister) Allie Caulfield (deceased brother) </Td> </Tr> <Tr> <Th> Nationality </Th> <Td> American </Td> </Tr> </Table> <Tr> <Th_colspan="2"> Holden Caulfield </Th> </Tr> <Tr> <Td_colspan="2"> An interpretation of Holden Caulfield on the cover of the 2012 book The Catcher in the Rye and Philosophy by Heather Salter and Keith Dromm . </Td> </Tr> <Tr> <Th> First appearance </Th> <Td> "I'm Crazy" </Td> </Tr>

How old is holden caulfield at the end of the book