Spot seasonal patterns in weekly or monthly figures

Examine the following series of figures for seasonal patterns.
Metric and figures: [Figures]
Period and interval: [Period]
What you want to know: [Question]
Approach: 1. Check whether the data is long enough to say anything about seasonality, at least two full cycles, and say so openly if not. 2. Show the recurring pattern as an index per month or weekday where 100 is the average. 3. Separate the trend from it, for example with a moving average or a comparison with the same period a year earlier. 4. Mark outliers and possible one-off effects such as public holidays, promotions or supply problems. 5. Answer the question with seasonally adjusted figures and state how certain the answer is.
Output: short table with the seasonal index, the trend in one sentence, a list of outliers and the answer. Calculate only with the figures provided.

Take particular care to separate season, trend and outliers cleanly and say openly when the data is not enough.

Before you answer, check: Are all instructions met? If key information is missing or a placeholder in square brackets is still in the text, ask instead of guessing. Mark assumptions as assumptions.​