http://www.mirrorlessrumors.com/japan-f ... -analysis/They link from there to the original source and electronic translation of full article if you want to dig deeper.
Take away points are:
With a bit of variation, Olympus are leaders in sales.
Panasonic have been on a downward trend for several months now, dropping into 3rd place.
Sony have been climbing over a similar period, taking a slight dip compared to September but takes a solid 2nd place.
Nikon were ahead of Sony earlier in the year, but didn't gain traction and is currently ranked 4th.
Pentax are a surprise to me, hovering above the 5% line. Someone is still buying them!
Canon, the latest entry to the world of mirrorless, is showing signs of climbing already passing Pentax with 9% of sales. If they can maintain the momentum is another matter...
And last but not least, is Fuji. They're barely on the scale. I guess their models are rather high end so would never count significantly in volume, in a similar way Leica wouldn't show either.
If they did ranking by revenue, the balance may be different than unit sales. There is also a list of top 10 models sold, and generally they're lower priced models. In the mirrorless vs. SLR balance, mirrorless are on around 45% share (exact value not given).