I tried to work out the context for this figure, but the answer I found made no sense. It's frustrating that I'm having to figure this out myself rather than The Guardian being responsible.
From https://en.wikipedia.org/wiki/Demographics_of_Qatar there are approximately 2.3 million migrant workers in Qatar. For 6500 of them to die over 10 years is a death rate of 6500/(10*2300000) = 0.000283.
The typical such worker is perhaps an Indian immigrant in the 35-39 age bracket. According to https://apps.who.int/gho/data/view.main.60740?lang=en such people would have a death rate of 0.00319, if they remained in India.
So have I made a mistake, or is this article really about the fact that being a near-slave in Qatar cuts your risk of death by 91%?