PARIS,  (DNA) – Millions of dead and millions more wounded, widowed and orphaned: the dizzying tolls from World War I are an indication of the scale and horror of the 1914-1918 conflict.

A lack of reliable statistics from the 52-month war a century ago makes the figures difficult to pin down, accounting for the sometimes substantial variations between historians.

Here s a compilation of the most widely accepted figures from the Great War, providing estimates in cases where major discrepancies remain.

More than 70 nations

Even this figure is tricky since many of the more than 70 current-day nations that were drawn into the conflict had yet to gain independence from the six empires and colonial powers at its heart: Austria-Hungary, Britain, France, Germany, Russia and the Ottoman empire.

A dozen independent nations went to war at its start in 1914, the rest entering later, such as Italy in 1915 and the United States in 1917.

Together the warring nations accounted for more than 800 million people, more than half the world’s population at the time.

Only around 20 countries across the globe were to remain neutral throughout the conflict, most of them in Latin America or northern Europe.

About 20 million men were mobilised by the warring parties at the outset, the number rising to around 70 million as the war dragged on and expanded.

There were eight million soldiers from France, 13 million from Germany, nine million from Austria-Hungary and six million from Italy.

Britain sent nine million men, including from around the British empire, chiefly India. The United States deployed four million.

Germany and Russia suffered the highest numbers of dead and wounded, with 10 million soldiers generally estimated to have been killed and double that number wounded overall.

Broad Breakdown by country

Russia: two million dead, five million injured;

Germany: two million dead, 4.2 million injured;

France: 1.4 million dead, 4.2 million injured;

Austria-Hungary: 1.4 million dead, 3.6 million injured;

Britain and British empire: 960,000 dead, two million injured;

Italy: 600,000 dead, one million injured;

Ottoman empire: 800,000 dead;

United States: 117,000 dead.

Serbia suffered the worst losses proportional to the size of its army with 130,000 dead and 135,000 wounded, three-quarters of its forces.

The opening weeks of the war exacted the heaviest human toll. For example, 27,000 French soldiers were killed in a single day on August 22, 1914, the deadliest day in the history of the French army.

Artillery fire caused 70 percent of the casualties in the war, after which between five and six million men were left mutilated for life.

The conflict saw the first large-scale use of chemical weapons when German forces deployed chlorine gas at Ypres in Belgium in 1915.

Toxic gas eventually claimed 20,000 lives over the war.

Between five and 10 million civilians are estimated to have been killed in the war and its consequences, which were many and make a precise figure difficult to establish.

The toll generally includes those killed in the actual fighting as well as from the resulting forced displacements of populations, famine and the subsequent civil conflicts in Russia, eastern Europe and Turkey.

Some historians include the disputed figure of 1.2-1.5 million Armenians massacred in the Ottoman empire.

A Spanish influenza epidemic that broke out at the end of the war and spread across the world claimed tens of millions of lives in Europe.