G-7 vs G-20

Since 2005, the G-7 share of world GDP has declined, while the G-20 share has stayed about the same.

Most of that change is from growth of China (the largest economy in the G-20, but not the G-7). Those 13 "other" countries are currently about 1/3 of the global economy, and China is between 1/2 and 2/3 of that.

There's a few things to note. 

First, this does not reflect the G-7 countries doing badly (having said that, most of them haven't done that well over those 20 years). 

Second, it does reflect the other 13 countries doing well. This is good for humanity; most of these countries weren't doing that well before the 21st century.

Third, since this is about GDP, it doesn't tell us about richness or welfare. Just size.

Fourth, GDP growth comes from increases in labor, capital, and technology. There is no breakdown here, so it's possible that the increasing share is driven completely by an increasing share of population. It isn't ... but population growth rates tend to be higher in poorer countries, and that's going to tend to tilt the share of the G-7 downward.

Infographic published as part of the page entitled "Charted: The G7's Declining Share of Global GDP" from Visual Capitalist.