No, most markers won't know. Except for the big, main, important, reported-in-the-news ones - such as the unemployment rate, the inflation rate, the economic growth rate, latest Gini coefficient.
If your stats are ballpark, then they won't care at all. They never bother to check. Also, if you make up stats, make them up for specific topics (e.g. the % increase in crude oil exports to China and Japan together over the last 5 years - a bit of exaggeration but you get what I mean).
This is something not to worry about (that much), trust me, half of my stats in the HSC External were made up and I ended up doing well anyway.
So, in summary, go for it, but with common sense and a bit of restrain.
Hope that helps!