During the 1970s, Baghdad experienced a period of prosperity and growth because of a sharp increase in the price of petroleum, Iraq's main export. New infrastructure including modern sewerage, water, and highway facilities were built during this period. The masterplans of the city (1967, 1973) were delivered by the Polish planning office Miastoprojekt-Kraków, mediated by Polservice. However, the Iran–Iraq War of the 1980s was a difficult time for the city, as money was diverted by Saddam Hussein to the army and thousands of residents were killed. Iran launched a number of missile attacks against Baghdad in retaliation for Saddam Hussein's continuous bombardments of Tehran's residential districts. In 1991 and 2003, the Gulf War and the 2003 invasion of Iraq caused significant damage to Baghdad's transportation, power, and sanitary infrastructure as the US-led coalition forces launched massive aerial assaults in the city in the two wars. Also in 2003, a minor riot in the city (which took place on 21 July) caused some disturbance in the population. The historic "Assyrian Quarter" of the city, Dora, which boasted a population of 150,000 Assyrians in 2003, made up over 3% of the capital's Assyrian population then. The community has been subject to kidnappings, death threats, vandalism, and house burnings by al-Qaeda and other insurgent groups. As of the end of 2014, only 1,500 Assyrians remained in Dora. The Iraq War took place from 2003 to 2011, but an Islamist insurgency lasted until 2013. It was followed by another war from 2013 to 2017 and a low-level insurgency from 2017, which included suicide bombings in January 2018 and January 2021. Priceless collection of artifacts in the National Museum of Iraq was looted by the Iraqi citizens during the 2003 US-led invasion. Thousands of ancient manuscripts in the National Library were destroyed.