Various estimates of DoD spending

[nitpicker]

The official DoD budget documents state the following for post-9-11 funding:
http://comptroller.defense.gov/Portals/45/Documents/defbudget/fy2017/FY2017_Budget_Request_Overview_Book.pdf

The historical funding picture is summarized in Figure 1-2:
Figure 1-2. Department of Defense Topline Since September 11th Attacks
($ in billions) FY 2001 FY 2002 FY 2003 FY 2004 FY 2005 FY 2006 FY 2007 FY 2008 FY 2009
Base 287.4 328.2 364.9 376.5 400.1 410.6 431.5 479.0 513.2
OCO 22.9 16.9 72.5 90.8 75.6 115.8 166.3 186.9 145.7
Other* 5.8 -- -- 0.3 3.2 8.2 3.1 -- 7.4
Total 316.2 345.1 437.5 467.6 478.9 534.5 600.9 665.9 666.3

($ in billions) FY 2010 FY 2011 FY 2012 FY 2013 FY 2014 FY 2015 FY 2016 FY 2017 (FY 16 and 17 est)
Base 527.9 528.2 530.4 495.5 496.3 497.3 521.7 523.9
OCO 162.4 158.8 115.1 82.0 84.9 63.0 58.6 58.8
Other* 0.7 -- -- 0.1 0.2 0.1 -- --
Total 691.0 687.0 645.5 577.6 581.4 560.4 580.3 582.7

Wikipedia states:

The following is historical spending on defense from 1996-2015, spending for 2014-15 is estimated.[10] 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.


Defense 96 97 98 99 00 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15
Budget
(Billions) 266 270 271 292 304 335 362 456 491 506 556 625 696 698 721 717 681 610 614 637
Total
Budget
(Trillions) 1.58 1.64 1.69 1.78 1.82 1.96 2.09 2.27 2.41 2.58 2.78 2.86 3.32 4.08 3.48 3.51 3.58 3.48 3.64 3.97
Defense
Budget % 16.8 16.5 16.0 16.4 16.7 17.1 17.3 20.1 20.4 19.6 20.0 21.9 20.9 17.1 20.7 20.4 19.1 17.5 16.8 16.0
Defense
Spending
Change -0.1 1.6 0.2 7.8 4.0 10.1 8.2 26.0 7.6 3.1 10.0 12.5 11.3 0.2 3.4 -0.6 -5.0 -10.5 0.6 3.8


This does not include many military-related items that are outside of the Defense Department budget, such as nuclear weapons research, maintenance, cleanup, and production, which are in the Atomic Energy Defense Activities section,[16] Veterans Affairs, the Treasury Department's payments in pensions to military retirees and widows and their families, interest on debt incurred in past wars, or State Department financing of foreign arms sales and militarily-related development assistance. Neither does it include defense spending that is not military in nature, such as the Department of Homeland Security, counter-terrorism spending by the Federal Bureau of Investigation, and intelligence-gathering spending by NSA.

[nitpicker]

1. The Nader article must have been penned in 2013 or 2014

At that time, the latest DoD updated expenditures would have been for FY 2012, which was ALMOST twice that of FY 2002 (relatively minor operations in Afghanistan).

Since then, sequestration (and the drawdown in Iraq) lead to DoD expenditures of under $600 billion a year from FY 2013 through FY 2015. For FY 2005, expenditures were about $479 billion. A jump, but if the $479B was inflated at 3% for 10 years..

As far as auditing DoD goes, it's been an effort to get individual departments (e.g. Marine Corps) to get ready to have their current years' activities be auditable. The DoD IG had to pull Grant Thornton's unqualified opinion on the Marine Corps financial statements after issues were found with that audit. http://goingconcern.com/post/grant-thornton-has-starring-role-marine-corpss-snafu-audit

Other firms have had to resort to opinion disclaimers with respect to the other services.