Charles Minard made a statistical graphic representation of Napoleon's attempt to take Russia. It's considered a classic example of how to display data in a format that lets the viewer immediately grasp the information. The absolute horror of the campaign is written large on this map.
Napoleon entered Russia with 442,000 men. On the original full sized graphic, each millimeter of width represented 10,000 men. Including the men diverted on the march east at the top of the graphic and rejoining the march west at the bottom, the surviving column as it leaves Russia is one millimeter wide. Ten thousand men, starving and ruined, returned to France. Troops that been conscripted from other countries are not listed here, but might have been as many as 150,000 and they suffered casualties at similar rates. One might imagine that the Russians took some losses as well.
One campaign. In one year, starting in June of 1812 and ending by the spring of 1813.
Napoleon promptly started building a new army. It would also pay a high price a couple of years later at a place called Waterloo.