I think such data across the year is very useful. Brings out interesting aspects like seasonality within particular trains, trains which have it on a regular basis etc. There have been 172 postings since November 2011 ie exactly 7 months ago. I feel many would love this kind of data in its raw form and if it is consolidated after the completion of one year. To my mind this the only 'rail' oriented data collected over a period of time.