On February 28th I wrote that I had just installed a 20,000 hour light bulb. Yesterday it burned out. It burned at night for seven months and 10 days; about 220 days, give or take a few. I turned it on when it began to get dark in the evening, and I turned it off when I got up in the morning. I won't bother with fancy estimates; let's just say it burned for 12 hours a day for 220 days, or 2,640 hours, which is about 13% of the promised number of hours. This country is going to hell in a hand basket.
I assume you know who the manufacturer is: write a letter of complaint. That's *waaay* too short a bulb life for what was advertised.