Whether it is to calculate the weight of the component or the component's volume, according to the idea of this percentage to apply the values to use in outreach work.
It calculates the weight of the composition or volume of a given element will be in the form of a percentage, to facilitate the introduction and use in the field.
Whether it is to calculate the weight of the components or the volume of components is not thinking in the form in order to facilitate the percentage values to use in the field.