It concerns me that these figures rely entirely on official Catholic estimates, given the obvious interest this source has in overstating the actual numbers. Further, this seems to be a consistent trend – see the following sources:
www.smh.com.au/text/articles/2008/04/30/1209234957542.html
www.findarticles.com/p/articles/mi_m0MKY/is_15_26/ai_94043378
Consider also for a moment the ubiquitous discrepancy between police and protestor attendance estimates at political rallies.
IMHO attendance figures should be removed unless they are verified by a reasonably independent source. Alternatively, it should be highlighted that these are figures directly from the Catholic Church.
Interestingly, it would be quite easy for the Catholic Church to provide official pilgrim numbers, as they are required to register their attendance.