Although the number of millionaires, and affluent of all levels, continues to increase, wealthy investors still say achieving the American dream is getting harder, according to a recent survey by Spectrem Group.

The number of millionaires, measured by total assets not counting their primary residence, increased for the third year in a row to 8.6 million by the end of 2011, according to the Spectrem Group Affluent Market Insights 2012.

The number is still below the peak of 9.2 million achieved in 2007 but is rebounding as the stock market starts to recover. The number hit a low of 6.7 million at the end of 2008.

The ranks of all affluent investors is increasing, with those with $25 million or more in net worth growing to 107,000 in 2011 from 105,000 in 2010; those with $5 million or more increasing to 1.078 million from 1.061 million in 2010; those with $500,000 climbing to 13.8 million from 13.5 million a year ago; and those with $100,000 reaching 36.7 million from 36.2 million in 2010, Spectrem said.

Despite their increasing portfolios, the wealthy are still worried about the future, according to the survey. More than four out of five of the total surveyed say achieving the American dream will be harder for future generations. Spectrem, a strategic consulting firm specializing in the affluent and retirement markets, surveyed 12,519 investors for the study.

The definition of the American dream differed by age, with those under 40 describing it as owning a home and those over 40 saying it means having sufficient retirement assets. All agreed the American dream means having "an equal opportunity for all people."

Although respondents' level of totals assets for purposes of the survey did not include the primary residence, they were asked how much their home represented compared to the rest of their assets. For those with $5 million or more in net worth the home was valued at 9% of total assets, for those with $1 million to $5 million the home was worth 16% of total assets, and for those with $100,000 to a million the home was 29% of total assets.

"Even if they are not directly impacted, continuing high unemployment and the depressed housing market are bedeviling wealthy investors," said George H. Walper Jr., Spectrem Group president. "Investor optimism has climbed from a negative in April 2011 to neutral in February 2012, according to our monthly Spectrem Affluent Investor Confidence Index," he said, "but investor outlook won't significantly improve until unemployment falls significantly lower."

-Karen DeMasters