If we're talking Britain, the biggest change over the last century is that it's become better quantified since Hoffmann's pioneering work in the 1930s & 40s, a little more recent in its impact (perhaps 1780-1860 rather than Toynbee's classic 1760-1830) thanks to Hoffmann and his contemporary Nef, more grounded in wider economic development since Deane & Cole's 1962 breakthrough study, and slower since the revisions of Crafts & Harley in the early 1980s (though Wrigley had pointed the way two decades before, Nef perhaps still earlier).

Since then, studies have largely merged into broader macroeconomic questions and international comparisons of income, productivity and potential for or constraints to growth: "Why Britain?" (sometimes subsumed into "Why the west?") It's a development I find generally less rewarding, often founded on calculations that seem far removed from the real economy. Of today's competing viewpoints (Crafts, Clark, Mokyr and others) I'd single out Allen's "high-wage economy" model as the most promising, though it could do with more explanation of its emergence.

Internationally, progress on Britain has been mirrored in the Americas and Europe, though earlier developments remain less clear: the last goes doubly for the rest of the world before the 20th century: it's widely accepted that Asia must have accounted for half of the world's manufacturing as late as 1800, but of its volume, structure, development and the scale of later de-industrialisation we know little despite various improbable portrayals of lands on the verge of a breakthrough but for some obstacle that hadn't previously made its presence felt.