If you've filled 140 seats on a 737-300 there isn't many left to fill and having looked at the prices from early on till more recently they have never been exactly rock bottom, I can't imagine them having a poor yield. Interestingly now the "they will be lucky to fill 20 seats" mob are nowhere to be seen now on here. A lot of the seats will be travel agency sold through the association with the Co-op.