ROE in indian markets are declining. why?

A report says ROE in indian co.s are declining. why?
https://www.livemint.com/Money/a34F...ets-up-despite-low-RoE-firms-dont-invest.html

 

ROE declined from 20 % in 2007 to 6.45% in 2015 which is below g-sec yield of 8.3%.

 

Does it depends on sample size? Method is changed? How there can be so much change in just one year. I think something is wrong somewhere.

 

not in one year. 2007 to 2015 ie, 8 years.

 

Ah, misread year. I think sample size has to be checked. Also sector has to be checked whether same or not. E.g. Steel sector or commodity sector may have high RoE earlier and low RoE now. Service sector may have low RoE then and high RoE now.

 

this figure may b avg of all listed co.s.-6.45%