Sarah, even that will not let you know if you have any degradation because, depending on numerous environmental factors out of your control, like wind strength and direction, temp, rain, snow, elevation gain, etc, your vehicle will use more or less energy every time. Even for the exact same trip. Other factors that you can control (like climate control, speed, etc) will also affect your range. Attached are a few plots I generated based on my usage since new. You will notice the pronounced seasonal effect, even though 70% of my driving is just my daily commute - so same trip every day. The black lines are the Hyundai rated values, ie, 200 km range, and 14 kWh /100 km consumption.
Also, it's worth noting that you are heading into your winter season right now, it's expected that you will loose range as the temp drops. However, it will return in 6 months. Six month later, the cycle will repeat. My 2018 IONIQ 28 kWh BEV has a little over 75,000 km right now and I don't see any measurable loss in range yet.
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