The number of U.S. financial advisors fell to 310,000 at the end of 2008, from 314,000 at the end of 2004.

Cerulli Associates, Boston, has published those figures in a report on hiring trends at broker-dealers.

The attrition rate for financial advisors may accelerate, because the average age of a financial advisor is about 49, and 14% are over 60.

In the insurance channel, advisors ages 41 to 50 account for the largest share (32%) of the field force, Cerulli says.

Only about 10% of advisors change firms in a typical year, but the churn rate increased to 13% in 2009, Cerulli says.

When Cerulli aggregated data from 1970s to the present, it found that wirehouses and insurance firms are the most common sources of new advisors, with 29% of new advisors coming from the wirehouses and 26% from insurers.