I downloaded 12,347 records of UK births, marriages and deaths of Blackmores from FreeBMD. I've done some analysis on these records and put it on the Data Collection portion of Blackmore Site.
One item to note is that FreeBMD only has the indexes fully transcribed from September 1837 to December 1931. Ancestry does have the indexes beyond 1931 and you can view them for free through most local libraries.
If you have any ideas for additional analysis of this data please pass it along and I'll try to accomodate your request.