The answer is “not all that long ago”
The very interesting Poverty Analysis blog points me to this graph and argument by Martin Ravallion (which I had missed):
From Ravallion writing on the CGD blog:
today’s rich countries had poverty rates in the early and mid-19th century that are comparable to those found in even relatively poor developing countries today.
…In most cases, their poverty rates fell dramatically in the 19th century (Japan was a late starter but caught up in the 20th century). Yet today there is virtually no extreme poverty left in today’s rich world, when judged by the standards of poor countries today.
when progress against poverty is measured as a % point per year it slowed down a lot toward the end (as can be seen in Figure 1).
More surprisingly, when measured in proportionate terms, experiences differed greatly… Some countries (the US, the UK, Japan) saw steady progress in proportionate terms, while others saw more erratic changes in rates of progress at low poverty rates.
While we often assume that it will be a long hard slog to get the last few percentiles out of extreme poverty, some rich countries maintained steady progress to the end, and some even accelerated.
My favorite, probably embellished, way of making the same point (rich countries recently had horrendous poverty) comes from George Orwell’s Down and Out in Paris and London. A great, great book.
Other equally interesting data and bits at the Poverty Analysis blog.