I am guessing that water in soil is the water contained in the upper layers of soil and dirt while groundwater is used for water reserves far under the ground much below the soil layers and even below the rock layers
Thinking the same thing. But now that I think about it, there is a lot of vegetation that would take up the majority of that share. Think about all the streama and rivers, then think about all the vegetation that surrounds and how easy it would be to fill those rivers with it. But still that's a lot of water.
Could just be that whatever was used to create the diagram has a minimum slice size and anything below that just gets rounded up. Without labels for the size of each slice it's impossible to tell.
Lake Baikal is the world's largestfreshwater lake by volume, containing 23,615.39 km3 (5,670 cu mi) of water or 22–23% of the world's fresh surface water
Living next to the great lakes, it never really hit me how unbelievably privileged I am to be able to swim in large bodies of freshwater until a few years ago. This chart definitely reinforces that.