WASHINGTON  The number of chronically homeless people living in the nation’s streets and shelters has dropped by about 30 percent  from 175,914 to 123,833  from 2005 to 2007, Bush administration officials said on Tuesday.

Housing officials say the statistics, which are collected annually from more than 3,800 cities and counties, may reflect better data collection and some variation in the number of communities reporting. But officials also attribute much of the decline to a policy shift promoted by Congress and the administration that has focused federal and local resources on finding stable housing for homeless people suffering from drug addiction, mental illness or physical disabilities, long deemed the hardest to help in the homeless population.

Under the strategy, known as “housing first,” local officials have over the last eight years increasingly placed the chronically homeless into permanent shelter  apartments, halfway houses or rooms  and provided them with services for drug addiction, mental illness and health problems.

Until cities and states began adopting the plan, many homeless people seemed to shuttle endlessly between emergency shelters, hospitals and the street. Officials and housing experts say the “housing first” program has begun to stabilize the chronically homeless population, which the administration defines as disabled individuals who have been continuously homeless for more than a year or have experienced at least four episodes of homelessness in the past three years.