The upshot of all this is that the marrow must be continually producing an enormous amount of new cells. When you add it all up, the figure actually comes out as 100 billion cells per day.
By far the most numerous cell type is the red blood cell (erythrocyte), which outnumbers white blood cells by 700 to 1. Platelets have a concentration of 150 to 450 million per millilitre. Overall, a typical thin smear of blood, once stained appropriately, looks something like this:
(a) points to two of the many red blood cells, (b) is a neutrophil, (c) is an eosinophil and (d) is a lymphocyte. Notice how many red cells there are, compared with other cell types. Those little dots in between the cells are mostly platelets.