Do people actually take the Utsa Patnaik $45 trillion and recent Oxfam numbers seriously?

Professor Utsa Patnaik estimated the magnitude of the British robbing of India thus:

"Between 1765 and 1938, the drain amounted to 9.2 trillion pounds ($45 trillion), taking India’s export surplus earnings as the measure, and compounding it at a 5 per cent rate of interest."

The methodology is shabby and the entire work seems only conducive to creating headlines.