This week ushers in the 5th anniversary of the start of the war in Iraq.

While war markers rarely bring a smile to the face as other anniversaries do, and while numbers are cold and sterile and harbor nothing of the humanity or gravity of such losses, they serve a useful purpose.

They ask that we observe, if only briefly, the sacrifices made for us half a world away.

Quick: Do you know how many troops have deployed, become injured, or even died so far? If you said 1.6 million (this first figure includes Afghanistan) have deployed you’d be on target. Toss in nearly 30,000 injured and nearly 4,000 killed in action in Iraq alone, and you’re totally engaged.

You’re lonely, too.

According to a Pew Research News IQ survey released last week, only 28 percent of us currently know how many U.S. troops have died in Iraq. This figure is down from 54 percent in August 2007. The indifference or even boredom reflects what’s going on in the media, too. War coverage made up only 3 percent of last month’s overall “newshole,” down from July 2007’s more generous 15 percent slice of the news pie.

The latest numbers offer one glimpse at the experience of our soldiers, sailors, airmen and Marines.

During the World War II era, about 12 percent of the U.S. population fought in the war. Today, only half a percent of us are

serving overseas. Over 500,000 have been deployed twice or more.

Nearly 37 percent (299,585) of our returning Iraq and Afghanistan veterans have received one form of medical treatment or another from their local Veterans Administration. About 40 percent of those patients (120,049) have been diagnosed with a mental health condition, 23 percent (67,717) with post-traumatic stress disorder. Studies show PTSD risk increases with multiple deployments.

Meanwhile, 663,000 veterans of all wars are waiting for their disability claims to be processed, the highest backlog on record. Hearing damage is the number one disability for today’s vets, with nearly 70,000 suffering from ringing in the ears and another 58,000 from hearing loss.

Improvised Explosive Devices, or IEDs, are said to cause the majority of these injuries. This 21st century menace is also responsible for the signature wound of the war, traumatic brain injury. At least 1-in-5 troops return home with mild, moderate or severe TBI.

For veterans returning to school after service, the GI Bill covers about $9,600 annually in tuition.

Unfortunately, yearly public university tuition averages about $16,000. Our local veterans do better in this area, having access to state funds that generally cover the lion’s share of their college costs.

Oceans of data exist on the Iraq War as well as all of those that came before it. One figure is often left off those rolls, however: the number that we, as a nation, should assign in our hearts and minds to our service members.

In my view, they’re number 1 in every way.