Why Does Google Display Not Up To Date Information?

It is good that Google provides features that anticipate what appears to be the information desired by a user. For example, it gives answers to mathematical expressions used as search queries (enter 3 + 3 in Google and it can act as a calculator, although Yahoo! Shortcut does the same thing)

But what I am wondering is why Google continues to display outdated information. I used Google to find the page that tells me what is the current unemployment rate in Hong Kong and entered “hong kong unemployment rate“. To my surprise, Google provided an answer to that question which is outdated. Google answered that the unemployment rate was 4.9% but this figure is still in 2006.

Why Does Google Display Not Updated Results?

Why Does Google Display Not Updated Results?

I’m sure Can Google provide more timely pieces of information and better not display an information if it’s not updated anymore?