In datasheet Figure 33. Resistor Lifetime Drift.
Please tell me measurement condition (Especially time and temperature).
My interpretation on Figure 33 is this. The graph shows how probable the part will drift and how much it will drift in its lifetime. This data should cover the whole temperature operating range (−40°C to +125°C)of the part.
If you are worried about failure rates, you can check up the analog.com website and loop up the reliability data for the part. I added the link below for your convenience.
Wafer Fabrication Data | Analog Devices