 Complete the following phrase:  Roughly 40 of Iraqs middle class is believed to have fled, the U.N. said. Most are fleeing systematic persecution and have no desire to return. All kinds of people, from university professors to bakers, have been targeted by militias, insurgents and criminals. An estimated 331 school teachers were slain in the first four months of 2006, according to Human Rights Watch, and at least 2,000 Iraqi doctors have been killed and 250 kidnapped since the 