I have a set of data (attached) which shows the volume of web traffic by Country, trended weekly. I'm trying to learn/find a statistical method that help me analyze the data in the following way:

- How much does it change? (Max, Min) -- I actually don't need an answer to this, I know how to do it, just reference for the second question below
- What is it's normal range? (Normal highs and lows, not maximums/minimums)
- What is the trend? (increasing, decreasing)

Are there statistical formulas to help understand this?