## How Many Divers Are There?

It's a simple question: how many certified scuba divers are actually out there? Unfortunately the answer is not so simple, for several reasons.

**Organizations don't share data.**Certification agencies tend to not release data about how many divers they certify. One exception is PADI, although they have been accused of inflating their numbers in the past. Without reliable numbers, it's much harder to get a good estimate.**Lack of trends.**For the few years that data is available, we can't extract any meaningful trends. For instance, we can't say anything as strong as "for 20 years diver certification has grown by 10% each year." The numbers seem too erratic to extrapolate.**Error.**The error also can be high, due to things like divers getting certifications from multiple agencies.

Despite these drawbacks, there have been several attempts at nailing down a number.

The best numbers we have are from DEMA, the Diving Equipment and Marketing Association. It is in their interests to know how many divers, and thus potential customers, are out there.

DEMA has data from three agencies (PADI, SDI, and SSI) for new diver
certifications between the year 2000 and 2008, seen below.

Using some fancy mathematics, we can see that in those 9 years, from those three agencies, 1,449,751 were certified. Unfortunately, as said before, these numbers are too erratic to usefully extrapolate. Also, we're missing numbers from NAUI, the second largest certification agency.

From here, it's time to start guessing. PADI provides some certification statistics that may help us guess intelligently.

The first thing you'll notice is that PADI's numbers are much larger
than the total numbers from DEMA. That's because PADI is counting
*total* certifications, not entry-level certifications. I assume this
includes things like specialties, which inflate the numbers for the past
few years up to almost a million certifications per year.

Let's adjust our 2000-2008 numbers to account for NAUI (and other organizations). I think it's safe to assume that doing so will inflate the number up to around 2,000,000 certifications.

Fortunately, we only need to consider as far back as around 1980---anything before that and the numbers are small enough to be within the margin of error.

If we use PADI's data to find a trend, we see that between the 90's and this decade, number of certifications increased around 35%. As there are more certified divers, there will be more advanced certifications and specialties, so let's say growth was 25%. That gives us 1,500,000 new divers for the 90's, and a total of 3,500,000 divers from 1990 to around present.

Doing the same thing for the 80's, we see growth was much larger as total certifications almost tripled. Let's say new certifications doubled, then. This results in about 750,000 new divers during the 80's. I'll round up to 1,000,000 to account for all previous certifications.

Using this very poor estimation strategy, we're looking at around 4,000,000 total certified scuba divers. What does this mean? Not much, really. There are lot of divers out there, most of which haven't been diving in years. I have no sense of how accurate / inaccurate this number might be, although I suspect it is low, due to the long tail provided by many smaller certification agencies. I wouldn't be surprised if the number was closer to 5 million, or even 10 million, for that matter.

Next time we'll look at how many *active* scuba divers are out there---a
more meaningful figure. In the meantime, **I'm curious to know in the
comments what you think of this number, and if you have suggestions for
improving our (poor) guesstimate.**

*Grouper photo by ansik*