When a statement of fact is made with regards to a variable, it means that the variable can be proven by actual evidence. Sometimes we may not be able to prove it ourselves so we leave that up to reputable people or organizations who specialize in the field of the variable in question.
Internet World Statistics is one such organization so if they say that there are a certain number of Filipino internet users in the country in a certain year, then chances are that it is a statement of fact because they have researched it and proven it to be true.