No one knows, with any certainty, how many people have been killed and wounded by bombs, bullets, and bombing-induced fire in Iraq since the US invasion in 2003.
But several facts are known:
— There are more than 133,000 individually recorded civilian deaths since the 2003 invasion of Iraq due to direct war related violence and tens of thousands of Iraqi civilians have been wounded.
Because all war-related deaths were not recorded accurately at the time by the relevant Iraqi ministries, or the US-led coalition, and there has been no complete census since 2003, observers must combine news reports with incomplete official counts.
The 133,000 number for civilians killed by direct war-related violence includes deaths recorded by official government sources and news media caused by all parties to the war — the US, its allies, the Iraqi military and police, and militants/insurgents. 
That number is low, perhaps very low, in part simply because not every direct war related death was recorded or reported. Further, reports and estimates for the number of Iraqi civilians killed have been clouded by arguments about methods for counting the dead and by politics inside Iraq and the US.
The violent deaths of Iraqi civilians have occurred through aerial bombing, shelling, gun-shots, suicide attacks, and fires started by bombing. 
— The number of individuals killed indirectly, because of the health effects of the destruction of Iraqi infrastructure and population dislocation, may be twice the number of direct deaths.
The damage and destruction to the systems that provide food, health care and clean drinking water in Iraq have contributed to many deaths due to illness and infectious diseases that could have been treated if Iraqi infrastructure not been destroyed.
In the absence of population census data, demographers must rely on randomly selected household surveys estimating the approximate numbers killed, injured, and made sick due to both the direct and indirect effects of war.
Several estimates have been based on such surveys —cluster samples of Iraqi households in randomly chosen areas. The most widely cited is a 2006 study published by The Lancet, which estimated more than 654,000 excess deaths related to the war, most of them violent deaths. 
A more recently published analysis, based on a 2011 survey of 2,000 households across Iraq, estimates the total excess Iraq deaths attributable to the war through mid-2011 to be approximately 405,000, with 56,000 additional deaths not counted due to migration of families of the deceased. 
— On-going war-related violence, and the failure to fully reconstruct war-damaged Iraqi infrastructure, continues to harm Iraqi men, women and children.
Despite more than $100 billion committed to aiding and reconstructing Iraq, the country remains devastated by the war. Many parts of the country still suffer from lack of access to clean drinking water and housing. The indirect harm will continue until medical and other infrastructure is repaired and fairly distributed.
The health of women and children is the most vulnerable in Iraq and many Iraqis are hungry, and dependent on rations. Mental health and rehabilitation services in Iraq are very stressed by the burden of care with inadequate resources. 
As Iraqis continue to die due to the direct and indirect effects of war-related violence, increasing numbers of children are orphaned and must live in institutions. Iraqi officials and orphanage staff struggle to care for Iraq's orphaned children in state facilities that are under-resourced and understaffed .
Approximately 1.5 million people remain either internally displaced or have fled the country; in other words, 1 in 20 Iraqis are still displaced from their homes.  Unemployment also remains high.
(Page updated as of May 2014)
 Iraq Body Count, (2014) http://www.iraqbodycount.org, accessed 17 March 2014.
 Hicks, MH-R, Dardagan, H, Guerrero, Serdán G, Bagnall PM, Sloboda JA, et al. (2011) "Violent Deaths of Iraqi Civilians, 2003–2008: Analysis by Perpetrator, Weapon, Time, and Location," PLoS Med 8(2): e1000415. doi:10.1371/journal.pmed.1000415. http://www.plosmedicine.org/article/info%3Adoi%2F10.1371%2Fjournal.pmed.1000415.
 Gilbert Burnham, Riyadh Lafta, Shannon Doocy, and Les Roberts, "Mortality after the 2003 invasion of Iraq: a cross-sectional cluster sample survey" (2006) The Lancet, 368 (9545) pp. 1421-1428.
 Hagopian, A, Flaxman AD, Takaro TK, Esa Al Shatari SA, Rajaratnam J, et al, “Mortality in Iraq Associated with the 2003-2011 War and Occupation: Findings from a National Cluster Sample Survey by the University Collaborative Iraq Mortality Study,” (2013), PLoS Med 10(10): e1001533. Doi:10.1371/journal.pmed.1001533, accessed 17 October 2013.
 The Lancet, Special Issue, 15 March 2013. http://www.thelancet.com/themed/iraq.
 Central Statistics Organization, Kurdistan Regional Statistics Office, Ministry of Health, and UNICEF, "Iraq: monitoring the situation of children and women," (2011), dl.dropbox.com/u/21257622/MICS4_Iraq_FinalReport_2011_Eng.pdf.
 “2013 UNHCR country operations profile—Iraq” (2014), http://www.unhcr.org/pages/49e486426.html, accessed 18 March 2014.