Please provide causes and percentages.
One of the first resources I found is a company that serves homeless people (adults and children) throughout the United States. I don't know your geographic area but hopefully this will help.
There are many reasons why people end up homeless and more reasons than there were years ago. With today's housing crisis, many families are losing their homes to foreclosures and have little to no money to rent an apartment or find a living space fast enough. These families often end up homeless for some time.
Mental illness and drug and alcohol abuse are two of the most prevalent factors that lead to people being homeless.
For many teenagers, they end up homeless because they can't get along with their parents and see no other way out except to run away.
According to Family Promise, 1 out of 50 children are homeless each year.
Also, 13% of Americans live in poverty and 42% of the children who are homeless are under the age of 6.
According to the above website, over the next two years, 1.5 million people will become homeless because of the economy - being laid off from their jobs, not being able to find jobs and the housing market crashing.
In 2008, there was an increase in homelessness in 19 out of the 25 cities surveyed with an average 12% increase since 2007.
The website above references a study done in 2008 by the US Department of Housing and Urban report ...
Current statistical data on homelessness in the United States, including recent trends and causes of homelessness.