I have to create a table similar to the one seen in the attached images. The table describes several systems with different parameters like volume etc.
In the second column I would like to give the number how often these systems exist in a certain plant. Unfortunately I have to keep the columns as short as possible to have enough space for the parameters.
What would be the shortest form in English to be used in the heading to indicate that the number/count of systems is meant. Are there any common abbreviations?