According to statistics compiled from the US Census Bureau, 2007 Economic Census, approximately 74% of the art sales for the year went to Households. The total value of all sales from art dealers was approximately $8,564,335,000, so approximately $6 billion worth of sales are attributable to household purchases. Art is a personal thing!
Coming in (at a not even close) second, with around 20%, is art bought by retailers and wholesalers... so it appears as though dealers themselves (of one kind or another) account for nearly the rest of the market share of art purchases (no doubt with the intent of selling later).
What's interesting is the minimal percentages from Businesses, Building, and Government, coming in at only 2% altogether (apparently they take that "percent for art" quite literally!). But that statistic might be a bit misleading: remember these are only sales reported by art dealers. Art acquired through different channels, through direct artist commissions via consultants, art funds, etc., aren't accounted for here (read more about the myriad ways art is bought and sold). But in any case, as most art dealers probably know already, it seems the best bet for art purchases are individual households!