Can sd cards get slower after almost a year

I have had this SanDisk micro Sd card for almost a year now and I noticed comparing tests from back then to now, the card is a little slower, about 5 MBytes/s difference. I was wondering if that was normal? I’ve tried doing research and from my understanding Sd cards do decrease in speed with time and use, however the exact time it takes for this to happen seems to be unclear.