I have a problem with calculating and interpreting ratios.

My team is suffering from huge data gaps and, therefore, we have no choice but to use all resources we have.

I want to calculate how many new buildings were built (per 100 buildings between 2001 - 2011) per population growth (% between 2001 and 2011). If I divide the first (proportion of new buildings) by the latter (population growth), what does this really mean?!

For example, one of the cities had a ratio of -1008. I know that this means that there was much more construction than population growth, but how can I interpret the number exactly? What does 1008 really mean?