Nearly 60% of American millionaire households get investment advice from a professional advisor and more than half of these households have become more conservative in their investing approach over the last year, according to a report from TNS Financial Services, a British market research firm.

The report also found that the number of American households with more than $1 million of net worth rose from 8.2 million in 2004 to 8.9 million in 2005. It’s the third consecutive annual increase. The average net worth for these households–not including the primary residence–is $2.16 million; average assets available for investments are $1.44 million.

TNS also listed the top 10 wealthiest counties in the U.S. Leading the ranking were: Los Angeles; Cook County, Illinois; and Orange County, California.

When asked to identify their single most important financial goal, the leading response of millionaire households was “to assure a comfortable standard of living during retirement.” Also on the goal list: leaving an estate for heirs, protecting their estate from taxes, minimizing income and capital gains taxes, improving household liquidity, and charitable giving. The average age for the head of a millionaire household is 58.–Ryan G. Murphy