The Japanese camera companies are predicting an approximately 10% growth in unit sales of cameras with interchangeable lenses this year. Is that realistic? Yes, absolutely. But it's also a double-edged sword. Much of the action will be in the low-end, mirrorless cameras, which last year took right around 10% of the market with only two real players (we now have four major players).
I'd say there's more than a good chance that the best case for DSLR sales is to remain relatively flat this year versus last (somewhere just above 9m units, or about 75-80% of the interchangeable lens category total currently estimated at almost 12m units). But I'm also unsure that mirrorless cameras are showing very strong growth. Recent retail outlet reports all seem to show that the initial burst of m4/3 sales has slowed a bit. That's probably due to the high prices of the these products compared to low-end DSLRs. Sony's recent introduction sets a new, lower price point for mirrorless cameras, and it'll be interesting to see how that plays and whether Olympus and Panasonic respond, and how aggressively. Mirrorless is likely to turn into a cat fight, but the two big cats have yet to awake from their afternoon nap.