250,000 was guess work....however it may not be bogus.
The complexities date back to 1945 and the state of medicine ever since. Operations that can be preformed today without blood had to be preformed with blood transfusions back in the day from the 1940's through the 1980's......... blood often made the difference.
Today blood is still a necessary part of treatment for traumatic injuries, birthing issues, blood issues, cancer treatment and a whole slew of additional treatments and conditions that we either don't realize or understand.
Here's just one case in point my sister went into surgery for ovarian cancer. Under the knife the surgeons ran out of time removing the cancer because she at that point needed to be transfused or she would have died on the table. She passed away two years later after chemo and other treatments. No one in the congregation remembered that first operation and the possibility that the no blood belief may have contributed to her death. How many times does that happen?
Third world countries where the JW's are getting new members often are at much higher risk medically speaking.
I usually point out that Jonestown caused the murder/suicide of close to 1000 believers. I wouldn't doubt that JW believers easily lose that many every year starting back in 1945. whether it's 70,000 or 250,000 it is still a shocking number to be associated with a misinterpretation of a bible law.
The Society was the only group that could have provided the information but for obvious reasons
that was the last thing they wanted to know.
I would also add that they are not only reckless with the health of their followers but also with the education and ability to provide a comfortable life for one's family.