I thought you were around in the 80s etc Arthur? Attendances now are higher than they were all the way through the 70s, 80s and 90s (maybe very slightly below 1999 but massively higher than most of the 70s/80s). We may not quite be at our peak of the early 2000s, but some of our biggest crowds back then were against the Bulls (two of the 2005 crowds were 20k plus against them). Take them out and we've not fallen much. Its also not fair to compare any season to one following one where we'd just won the championship for the first time in 30 years. Our average crowd at home in 2006 fell back to just over 14k, but then beat the 05 average in 2007. Success does have an impact.
I also think the percent of population metric is a bit off. RL has never been more than a small minority sport in Leeds compared to football. When I was at school I only knew two or three kids interested in RL. There were far more active Man Utd fans who travelled by train to watch "home" games than RL fans, also more Liverpool fans etc, and the vast majority of kids were supposedly Leeds Utd fans. On a percent of population basis vs Cas we ought to average 70k a week or something daft.
Just saying, I've been around long enough to know really cr*p times, and these aren't them. Also that the loss of Bradford to SL was a real damage to the sport.