You clearly have a large pool of hardware. Your numbers mean nothing without knowing the hardware that DIDN'T fail.
To give a more useful metric, for the last 4 years I have maintained a company have about 150 machines. 50% are Macbook Pros. 50% are Lenovos. I saw, on average, 5-6 Lenovos have some sort of hardware failure per year. The Macbook Pros would see 1-2 hardware failures per year. The Macbook Pros were also giving about 6-12 months of extra life before needing to be replaced. The external packaging of the Lenovos would produce MUCH more wear year over year than the aluminum Macbook Pro.
I believe the Lenovo is just a terrible hardware producer. I got a T410S when I started at my new company. It was brand new. 3 months later the screen had a 1" thick white line on the monitor. I treated the thing like royalty. A few months later the plastic casing started to crack despite the lack of obvious impacts. 6 months later, a fan error prevented it from booting. I bought a mac book air at the same time, and it's still looks/works like the day I bought it!
I have a Lenovo-built T60p, built in 2006, I own it since 2008, works like new and looks much better than you'd expect a six-year-old laptop. Anecdata!
To give a more useful metric, for the last 4 years I have maintained a company have about 150 machines. 50% are Macbook Pros. 50% are Lenovos. I saw, on average, 5-6 Lenovos have some sort of hardware failure per year. The Macbook Pros would see 1-2 hardware failures per year. The Macbook Pros were also giving about 6-12 months of extra life before needing to be replaced. The external packaging of the Lenovos would produce MUCH more wear year over year than the aluminum Macbook Pro.