On the whole, Mega Man is up one million units since 2011. Given that few new games released since then, the boost is probably attributed to digital re-releases of older titles. Free-to-play Rockman Xover and Street Fighter X Mega Man, million sellers in their own right, appear to be non-factor.
You can read additional data at Capcom's Investor Relation page here.
Source: Capcom Total Sales Units Data