What does Google keyword volume, tool give such low monthly search data ?

[Nirmala]

I am trying out the key word search tool in Google adwords. This gives the average number of times people have searched Google for a certain keyword. The numbers seem really low. For an example, when putting the search term "god" , according to the tool , only 450,000 people use that term per month. That is crazily low. In the past, Google had this tool on its own, without being embedded in adwords. I am sure the search term for god would have made the tools report millions of uses, instead of the current low number. Any insight would be great.
Sorry I meant to say "Why" in the question header.

[Jake]

The keyword tool was always made primarily for Adsense advertisers, they just recently removed public access.

People look for Good in different places, I don't know that many actually expect to find him on Google. Dont know if you are looking at local or global results, the exact match option is always going to give the most accurate results.

[Emerson]

It is an important to checkout the keyword volume before starting SEO. Google adwords is the best tool for checking all the local and global monthly search volume of the keywords.

[flying_ant_2013]

There is no tool or software out there, not even the Keyword Planner, which offers 100% accuracy. In the example that you posted, the numbers could be actually accurate if these are "exact searches" - I would also expect much higher monthly searches, but most of the searches are probably in the form of questions or phrases instead of just typing in the single word. Hope this makes sense