Trend? Growth? Mathematic approach needed.

Dear All,

I asked this yesterday…and I have even seen that someone had reply…but for one reason or another, the post has been deleted (don’t know why…) and I need to come back to this issue once again…

Let’s put this way: I have to estimate (or foresee) the number of item X sales for the upcoming years (2010-2018). I have the 2006-2009 sales numbers plus the number of customer visits recorded in those years. There is a relation between the number of customer visits and the number of sales (this is a key factor). Please check the attachment.

From the tables I can easily establish a relation between the number of sales vs. number of customer visits (how many customer visits needed to sale one item). I want to learn from this relation and establish one trend (key factor).

I also know that the number of customer visits will be 2000 from now on (2010-2018).

How many items am I expected to sell in 2010…etc? I’m puzzled whether to use “growth” or “trend” (I am not experienced in any of these formulas)…or it might be a completely different mathematic approach. Voice your opinions please!

Thanks in advance for your valuable help.

Regards.