If you go to:
UK Situation
...you will find the best set of e-cig stats in one place. However they are now out of date. It was possible to make a fairly accurate guess at certain figures in early 2011 because there were several sources of data that all agreed with each other, but any estimate now is just a guess. You could get in the ballpark by figuring between 25% to 50% growth per year, and adding it to those figures.
As for the number of ecigs sold, it is an uncountable number of millions. In early 2011 the US market was worth about $100m. No one knows how many e-cigs are sold per $1m although if you had to, you could work it out by asking a selection of vendors what proportion of their turnover can be attributed to e-cig units, e-liquid, etc, averaging it out, and figuring it out that way.
So if you want to do some research, ask half a dozen vendors what proportion of their turnover is for e-cigarette units as against other products. Also ask them the average cost of one e-cigarette unit.
- If for example the average answer is 40%, then assume 40% of all sales are e-cigarette units (which will be wrong, but anyway...).
- So 40% of every $1m is for e-cig units = $0.4m.
- Multiply by annual turnover for US
- In Q1 2011 that was c. $100m (this needs checking on the ECCA page).
- So in early 2011 we might think that $40m per year was being spent specifically on e-cigarette units in the US.
- Now we divide that by the average cost of an e-cigarette.
Then you have an approximate number sold per year. There are any number of reasons why this could be a mile out but it's a start.
If you show your sources, your calculations, and how errors can creep in, perhaps in an appendix, that sort of thing can add points in coursework.