One, and they are using GDP (nominal) https://www.visualcapitalist.com/charted-comparing-the-gdp-of-brics-and-the-g7-countries/

Many of BRICS’ current members already have real GDP growth rates that are higher than their G7 counterparts, with current members having an average GDP growth of 189% to 2050 compared to the G7’s average of 50%, according to Goldman Sachs.

BRICS’ newly added members like Ethiopia (1,170% GDP growth projected by 2050) and Egypt (635% GDP growth projected by 2050) have even higher rates of potential economic growth, further raising the bloc’s economic potential.