Just got off the phone...
...with a technical representative for Perfect Equipment in Tennessee. She told me that the lead based wheel weights they manufacture are from 93 to 99 percent lead with other metals being tin and antimony. She had no way of knowing:
1. How much change there is in the alloy and how fast....eg 93 percent today, 99 percent tomorrow, but she did believe it had to do with the cost of the metals.
2. Whether other manufacturers use similar alloys, although she assumed they do for market reasons.
3. How much of the market is supplied by Perfect Equipment.
If you look on the internet, you find that most of the manufacturers listed are Chinese.
My reading of history convinces me that most bad government results from too much government. Thomas Jefferson