After 2500 years of verbal tradition and 'internationalization' (translation into many languages for many cultures), it is wonderful to hear that 50% of original teaching remains. If we look at a polynomial expansion say (1 - 0.001) to the power of 2500th --> 0.08198. So, with just 0.1% dilution each year, after 2500 year, we can expect only 8.2 % of original material remains.

Incidentally, estimating how long would it take to dilute the original teaching to 50% if 0.1% is lost each year?

Using a simple 0.50 = (1 - 0.001)**x and solve for x = log(0.5)/log(0.999) --> x = 692.80 years. That about the time of King Asoka (c700 years after the time of the Buddha).

I wonder if King Asoka version of the Tipitaka is what we have managed to keep 'pure' today?

Anyway, it is difficult to be a Buddhist and a 'pure' Buddhist at that.

We have to swallow the sugar coating with the pill. ;-)