Here's the original source for the article:
http://www.publishers.org/press/30/
The FT article is a little bit misleading. The categories are broken into "Adult Hardcover, Adult Paperback, Adult Mass Market, Children’s/Young Adult Hardcover, Children’s/Young Adult Paperback." Ebooks are beating these individual categories, to wit:
February 2011:
All Ebooks = $90m
Adult print = $156m
Children's print = $58m
Religious = $48m
Education = $406m
Professional = $46m
So, ebooks clocked in at a little over 11% of sales in February, and likely cuts across all of the above divisions to a certain extent.