"In the treemap we could see lion share of total medals were going to few countries like Russia/USA back in 1980's but as time progressed in recent times we could see other countries are also pitching in.

"As the above line chart represents, gender inequality was significant untill 2008 But if you analyze developed nations like USA has rectified this problem way back in 1996 itself. Which could also be a reason for the rapid growth of these nations