There was an interesting graph in yesterday's The Japan Food Journal. The exact numbers were not given, but you can eye the graph and come pretty close. The graph was a monthly measure of beer sales by category (beer, happoshu, 3rd category) compared with the sales in the previous year.
Two factors are clear:
1) 3rd category beer is what is carrying the market while beer sales have suffered big setbacks. This is likely do to the large price differences which have been discussed in this blog before.
2) there appears to be an unexpected boom in beer sales. 3rd category beer sales in July were up 40% over last year, happoshu 3% and beer 2%. The likely reason for this is the unusually hot summer we are having.