For those in the financial services industry, the opinions and perspectives of affluent Americans - often referred to as the "mass affluent" crowd - are particularly important.

The more advisors know about these current and potential clients, the better they can serve them and bolster their assets under management.

These highly coveted clients, defined as adults aged 18 years of age or older living in households with at least $100,000 in annual household income, account for 25% (roughly 59 million) of the U.S. population.

Here's a closer look at what wealth managers need to know about this key demographic and what issues and concerns they?re grappling with today.

Sources: Stephen Kraus, chief insights officer of the Audience Measurement Group of Ipsos MediaCT, who also helps lead the Mendelsohn Affluent Survey. Spectrem Group?s June Affluent Investor Confidence Index.