- Air force > Combat aircraft: Number of fighter aircrafts (fixed wing aircrafts with combat capability).
- Armed forces personnel: Total armed forces (2000)
- Army > Main battle tanks: Number of main battle tanks.
- Battle-related deaths > Number of people: Battle-related deaths (number of people). Battle-related deaths are deaths in battle-related conflicts between warring parties in the conflict dyad (two conflict units that are parties to a conflict). Typically, battle-related deaths occur in warfare involving the armed forces of the warring parties. This includes traditional battlefield fighting, guerrilla activities, and all kinds of bombardments of military units, cities, and villages, etc. The targets are usually the military itself and its installations or state institutions and state representatives, but there is often substantial collateral damage in the form of civilians being killed in crossfire, in indiscriminate bombings, etc. All deaths--military as well as civilian--incurred in such situations, are counted as battle-related deaths.
- Expenditures > Percent of GDP: Current military expenditures as an estimated percent of gross domestic product (GDP).
- Global Peace Index: The Global Peace Index is comprised of 22 indicators in the three categories ongoing domestic or international conflicts; societal safety; and security and militarization. A low index value indicates a peaceful and safe country.
- Military branches: This entry lists the service branches subordinate to defense ministries or the equivalent (typically ground, naval, air, and marine forces).
- Military expenditures: This entry gives spending on defense programs for the most recent year available as a percent of gross domestic product (GDP); the GDP is calculated on an exchange rate basis, i.e., not in terms of purchasing power parity (PPP). For countries with no military forces, this figure can include expenditures on public security and police.
- Military service age and obligation: This entry gives the required ages for voluntary or conscript military service and the length of service obligation.
- Navy > Aircraft carriers: Number of aircraft carriers.
No date was available from the Wikipedia article, so we used the date of retrieval.
- Personnel: Armed forces personnel are active duty military personnel, including paramilitary forces if the training, organization, equipment, and control suggest they may be used to support or replace regular military forces.
- Service age and obligation: This entry gives the required ages for voluntary or conscript military service and the length of sevice obligation.
SOURCES: Wikipedia: List of countries by level of military equipment (List); IISS (International Institute for Strategic Studies). 2001. The Military Balance 2001-2002. Oxford: Oxford University Press; Uppsala Conflict Data Program, http://www.pcr.uu.se/research/UCDP/.; All CIA World Factbooks 18 December 2003 to 18 December 2008; http://www.visionofhumanity.org/#/page/indexes/global-peace-index, Global Rankings. Vision of Humanity.; CIA World Factbooks 18 December 2003 to 28 March 2011; CIA World Factbooks 2010, 2011, 2012, 2013; Wikipedia: List of countries by number of military and paramilitary personnel (The list); World Development Indicators database
"Yemen Military Stats", NationMaster. Retrieved from http://www.nationmaster.com/country-info/profiles/Yemen/Military
"Yemen Military Stats, NationMaster." 1985-2014. <http://www.nationmaster.com/country-info/profiles/Yemen/Military>.
'Yemen Military Stats, NationMaster', <http://www.nationmaster.com/country-info/profiles/Yemen/Military> [assessed 1985-2014]
"Yemen Military Stats", NationMaster [Internet]. 1985-2014. Avaliable from: <http://www.nationmaster.com/country-info/profiles/Yemen/Military>.
"Yemen Military Stats", NationMaster. Avaliable at: nationmaster.com. Assessed 1985-2014.
"Yemen Military Stats, NationMaster," http://www.nationmaster.com/country-info/profiles/Yemen/Military (assessed 1985-2014)
"Yemen Military Stats", NationMaster, http://www.nationmaster.com/country-info/profiles/Yemen/Military (last visited 1985-2014)
"Yemen Military Stats", NationMaster, http://www.nationmaster.com/country-info/profiles/Yemen/Military (as of 1985-2014)