<P> For the period 2010 - 14, SIPRI found that the United States was the world's biggest exporter of major arms, accounting for 31 percent of global shares, followed by Russia with 27 percent . The USA delivered weapons to at least 94 recipients . The United States was also the world's eighth largest importer of major military equipment for the same period . The main imports were 19 transport aircraft from Italy; and equipment produced in the US under license--including 252 trainer aircraft of Swiss design, 223 light helicopters of German design and 10 maritime patrol aircraft of Spanish design . </P> <P> The following is historical spending on defense from 1996 - 2015, spending for 2014 - 15 is estimated . The Defense Budget is shown in billions of dollars and total budget in trillions of dollars . The percentage of the total U.S. budget spent on defense is indicated in the third row, and change in defense spending from the previous year in the final row . </P> <Table> <Tr> <Th> </Th> <Th_colspan="4"> 1990s </Th> <Th_colspan="10"> 2000s </Th> <Th_colspan="6"> 2010s </Th> </Tr> <Tr> <Th> 96 </Th> <Th> 97 </Th> <Th> 98 </Th> <Th> 99 </Th> <Th> 00 </Th> <Th> 01 </Th> <Th> 02 </Th> <Th> 03 </Th> <Th> 04 </Th> <Th> 05 </Th> <Th> 06 </Th> <Th> 07 </Th> <Th> 08 </Th> <Th> 09 </Th> <Th> 10 </Th> <Th> 11 </Th> <Th> 12 </Th> <Th> 13 </Th> <Th> 14 </Th> <Th> 15 </Th> </Tr> <Tr> <Td> Defense Budget (Billions) </Td> <Td> 266 </Td> <Td> 270 </Td> <Td> 271 </Td> <Td> 292 </Td> <Td> 304 </Td> <Td> 335 </Td> <Td> 362 </Td> <Td> 456 </Td> <Td> 491 </Td> <Td> 506 </Td> <Td> 556 </Td> <Td> 625 </Td> <Td> 696 </Td> <Td> 698 </Td> <Td> 721 </Td> <Td> 717 </Td> <Td> 681 </Td> <Td> 610 </Td> <Td> 614 </Td> <Td> 637 </Td> </Tr> <Tr> <Td> Total Budget (Trillions) </Td> <Td> 1.58 </Td> <Td> 1.64 </Td> <Td> 1.69 </Td> <Td> 1.78 </Td> <Td> 1.82 </Td> <Td> 1.96 </Td> <Td> 2.09 </Td> <Td> 2.27 </Td> <Td> 2.41 </Td> <Td> 2.58 </Td> <Td> 2.78 </Td> <Td> 2.86 </Td> <Td> 3.32 </Td> <Td> 4.08 </Td> <Td> 3.48 </Td> <Td> 3.51 </Td> <Td> 3.58 </Td> <Td> 3.48 </Td> <Td> 3.64 </Td> <Td> 3.97 </Td> </Tr> <Tr> <Td> Defense Budget% </Td> <Td> 16.8 </Td> <Td> 16.5 </Td> <Td> 16.0 </Td> <Td> 16.4 </Td> <Td> 16.7 </Td> <Td> 17.1 </Td> <Td> 17.3 </Td> <Td> 20.1 </Td> <Td> 20.4 </Td> <Td> 19.6 </Td> <Td> 20.0 </Td> <Td> 21.9 </Td> <Td> 20.9 </Td> <Td> 17.1 </Td> <Td> 20.7 </Td> <Td> 20.4 </Td> <Td> 19.1 </Td> <Td> 17.5 </Td> <Td> 16.8 </Td> <Td> 16.0 </Td> </Tr> <Tr> <Td> Defense Spending% Change </Td> <Td> - 0.1 </Td> <Td> + 1.6 </Td> <Td> + 0.2 </Td> <Td> + 7.8 </Td> <Td> + 4.0 </Td> <Td> + 10.1 </Td> <Td> + 8.2 </Td> <Td> + 26.0 </Td> <Td> + 7.6 </Td> <Td> + 3.1 </Td> <Td> + 10.0 </Td> <Td> + 12.5 </Td> <Td> + 11.3 </Td> <Td> + 0.2 </Td> <Td> + 3.4 </Td> <Td> - 0.6 </Td> <Td> - 5.0 </Td> <Td> - 10.5 </Td> <Td> + 0.6 </Td> <Td> + 3.8 </Td> </Tr> </Table> <Tr> <Th> </Th> <Th_colspan="4"> 1990s </Th> <Th_colspan="10"> 2000s </Th> <Th_colspan="6"> 2010s </Th> </Tr>

What percentage of the united states budget is spent on defense
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