'India's Contribution to the Great War' published by authority of the Government of India in 1923, contains page after page of statistics setting out the human, financial and material cost of the First World War
For example - India contributed equipment and stores worth over £80 million to the Allied war effort.
That figure was the amount they contributed then hard to calculate its relative value today but here is another statistic:
In the context of Britain: £100 in 1917 would be worth £34,000 today.
This is estimated using the share of GDP as an indicator.
GDP, the economy's total output of goods and services in money terms, is the best measure of relative value for large-scale projects or expenditures, such as government expenditure on defence.
There are detailed records listing exactly what these supplies were:
In terms of direct monetary contribution India gave:
£146.2 million from its revenues up until 1920
An initial offer of a lump sum of £100 million was made in 1917. Three quarters of this was raised by war loans or bonds and the rest by the Government of India.
A government may issue war bonds for the purpose of financing military operations. The yield is generally very small - so, for example, if a bond matures in 10 years someone may only expect as little as 2% return. To buy a war bond was seen as an act of patriotism.
This letter and postcard from 1918 bear stamps, in Urdu on the postcard, entreating people to buy war loans.