I don't think you would ever be able to get an exact figure.
However right from amateur to professional level you get insurance against death when you are a player.
At London Irish Amateur its £1million. Proffesionals would be many multiples of this.
Deaths in rugby would most likely come from kneck, head or back injuries.
The true number of total deaths is unknown since rugby was created 1823 and also because rugby is so world wide. A few stats have appeared from time to time, such as between the years 1890-1893, 71 players in England alone were killed due to rugby related injuries. Since then the IRB (International Rugby Board, created in 1886) regulated rules as to what a safe tackle is. Yet since then there have still been possibly many thousands of players killed mostly within amateur, college level, and youth level playing world wide. Now a days hits are regulated even more for players safety yet incidents still occur both by malicious intent or accident (i.e. Early October 2010 Brendon Leonard made accidental head to head contact with Lachie Munro in the ITM Cup. Causing severe head and spine damage to Brendon and causing him to bleed from the ears and become unconscious for several hours.) Many players careers have been ended and others lives have been changed as a whole due to rugby injuries mostly paralysis or loss of movement in limbs, loss of limbs, or loss of vision due to the venomous eye gouge. Cheap hits (i.e. cleat stomps, spear tackle, eye gouging, tackle drops, or dives...ext.) still pose a serious problem which have lead to deaths and many injuries, the IRB has worked to crack down on these by banning the assailant for multiple games, years, or from a life of rugby.
Many people where rugby is less popular (i.e. United States) still look at rugby as "wimpy" due to it's "less impacting hits" now a days. Yet with 180+ years of playing and regulations plus possibly many thousands of deaths in it's history world wide at all levels (thankfully getting less as the years move on), and it's millions of injures some of which are life changing...I'd say they knew what they were doing. Rugby still poses a serious risk to anyone who plays it (like me), rugby hits should not be taken lightly as some hits that seem light are in fact putting near a thousands of pounds (sometimes more) of force on an unarmored body.