Numbers are up for engines below 3.0 liters, while displacements smaller than 2.0 liters actually saw a decline for 2009. While engines between 2.0 and 2.9 liters are perhaps not as exciting as the typically larger V6 and V8 engines, they're less expensive and can still provide satisfying performance thanks to improvements like direct injection and forced induction. It's also worth noting that production numbers for trucks dropped for 2009, as well, skewing numbers further in favor of smaller engines.
Ward's comprehensive analysis of different engine sizes and types and their market share and volume lays it out for you in the link below. Either way, we suspect that the garages of car nuts are still filled with a majority of high-performance engines, regardless of displacement or cylinder count.
[Source: Ward's Automotive]