How many Palestinians are there in Gaza?

No, this is not a tasteless, "how many Palestinians does it take..." joke.  We really want to know: what is the Palestinian population of Gaza?  The reason we're baffled is because Reuters seemingly can't make up its mind as to the correct figure.  On July 5, 2010, Reuters correspondent Ibon Villelabeitia wrote:

Once Israel's closest Muslim ally, Turkey has said several times it wants Israel to apologise over the May 31 raid, pay compensation, agree to a U.N. inquiry into the incident and lift the blockade of 1.6 million Palestinians living in Gaza Strip.

Then, on August 7, 2010, Reuters correspondent Nidal al-Mughrabi informed us:

Officials from the Islamist Hamas faction that runs the Gaza Strip, home to 1.5 million Palestinians, blamed the disruption on the rival Western-backed government of Palestinian Prime Minister Salam Fayyad based in the West Bank city of Ramallah.

But three days later, if we are to believe al-Mughrabi, the Palestinian population in Gaza had apparently ballooned by 200,000 souls:

It also aggravates the privations of 1.7 million Palestinians in Gaza, many of whom depend on U.N. aid.

Come on guys, do we have to do a headcount?