Private financing is leading a boom in documentaries -- as evidenced by the record number screened at the 36th Toronto International Film Festival, wrapping up on Sunday. A growing number of filmmakers have also been drawn to the genre's low production costs (usually less than $500,000 to make a documentary) and freedom from studio oversight, organizers said. "We've seen this sector grow more and more every year," said Thom Powers, lead documentary programmer at the festival, which opened for the first time ever this year with a documentary, about Irish rock bank U2. From September 8 to 18, the Toronto film festival -- the largest in North America -- will have screened 268 feature films, including 30 documentaries. "For a long time broadcasters were the main source of financing (for documentaries) but now filmmakers are attracting private investment money," said Powers. Others, like New York director Gary Hustwit's "Urbanized," which premiered at the Toronto film festival, some are raising money "directly from the Internet" by appealing to audiences and asking them what they want to see. Powers calls it "crowd funding." Websites such as Kickstarter.com and Indiegogo.com are among some of the websites facilitating such direct fundraising. "It's an important growth area for filmmakers to raise money," he said. "It's a very exciting new trend that means filmmakers no longer have to go through (studios or broadcasters), the gatekeepers of money." Also, with documentaries "you can target a specific audience, for example, with 'Urbanized' they targeted people who are passionate about urban planning, architecture and design." Hustwit, who previously profiled the makers of graphics and household objects in "Helvetica" (2007) and "Objectified" (2009), looks at new strategies for meeting the challenges of cities, such as expanding Mumbai and shrinking Detroit, in his new film. The acclaimed director takes audiences on a tour of new models for low-incoming housing in Santiago, unique walking paths in Cape Town that helped reduce violence by 40 percent, and Bogota's plan to put public transportation ahead of automobiles. Directors such as Werner Herzog ("The Enigma of Kaspar Hauser"), Cameron Crowe ("Jerry McGuire" and "Almost Famous) and Win Wenders ("The Buena Vista Social Club") are also being drawn to the genre, said Powers, because it is liberating. "They have more freedom of expression with documentaries because there isn't as much money or industry pressure, and you don't have to set up and travel with a big crew, trailers for stars, etcetera," he explained. The film festival opened last week with a documentary on the Irish rock band U2's dizzying rise to superstardom and near break-up, "From The Sky Down." It was directed by Davis Guggenheim, who won an Oscar in 2007 for "An Inconvenient Truth," a documentary on climate change featuring former US vice president Al Gore. Since then, documentaries have actually outpaced their fictional counterparts at the festival box office, one on one. (Toronto is coincidentally also host to one of the world's largest documentary film festivals, HotDocs). Other films at the Toronto International Film Festival this year are documentaries about Neil Young and Pearl Jam; the history of film (Mark Cousin's "The Story of Film: An Odyssey"); water woes (Jessica Yu's "Last Call at the Oasis"); the Maldives' fight against climate change ("The Island President"); problems caused by new technologies ("Surviving Progress"); the fallout of Egyptian president Hosni Mubarak's downfall ("Tahir 2011"); the death penalty ("Into the Abyss"); and US politics ("Sarah Palin -- You betcha!").