Well, I don't think the amount of Bitcoin revenue that could be made right now with Bitcoin payments is enough to convince any bigger company.

The best approach would probably bee to sell it to them as some kind of marketing gag.

Pros would be:

• They present themselves as fast (first?) adopters of new technology, therefore they stick out from their competitors
• They get (a tiny) additional income from they Bitcoin community
• There is zero financial risk involved with accepting Bitcoin payments, even if there will never be a Bitcoin payment, it cost absolutely nothing
• The are virtually no setup expenses with accepting BTC payments

As for your graphs, as there is no central authority in BTC, its difficult to now for sure how much BTC business there is. The most impressive graph is probably the growth of BTC transactions:




For numbers for Germany, you could ask the users Bitcoin_de who runs bitcoin.de

and TAiS46 who runs bitcoin-24.com

Maybe they can help you out.

To make this clear. We will offer this payment method for free to our customers, so it's not for our selfs.
Only to prevent the problem of only 3 out of the 1500 customers a year for instance using this we want to know some numbers before we launch this.

Weird stuff. Why are there no concrete numbers to find? This is what companies need and demand before they are even gonna start to consider if they should accept Bitcoin or not.
Even with a $18 bounty nobody is able to find any good numbers for Germany, Netherlands and Belgium?

Is this about the bounty or about the pure fact there are no real good stats of this?

Tell them about wordpress (alexa traffic rank: #23),
use some charts from here:
https://blockchain.info/charts

Bitpay has signed up their 10k'th customer:
http://www.businesswire.com/news/home/20130122006045/en/BitPay-Surpasses-10000-Bitcoin-Merchant-Transactions-Cases
dont know about the Denmark based WalletBit, though.

An incomplete list of merchants here:
https://en.bitcoin.it/wiki/Trade

and the corresponding thread tracking its growth (will be updated as soon as some coding is done):
https://bt.irlbtc.com/view/35083.0

Tell them about the general advantages of Bitcoin, like instantaneousness (wow, cool word), charge free-ness, no fraud, cant be frozen, anonymous (you can always know your customer if you want), ...

There are various plug ins for shopping carts available already (wow 33 already!):
https://en.bitcoin.it/wiki/Category:Shopping_Cart_Interfaces
and here:
https://bitpay.com/bitcoin-shopping-cart-plugins


Keep the change;)
Good luck

Alright here is the story.
I work at a company in the Netherlands that provides an hosting cart solution.
We have over 1700 customers now and are also expanding to Belgium.
Next to this we also offer add-ons (wich are modules you can add to your webshop), and we do custom work.
We also offer seperate payment methods wich you can install in your webshop.
Think about Paypal,  iDeal, Bank transfer, Creditcard, Giftcards, Postpay methods.
And now I also wanted to offer Bitcoin. The module is fully developed and tested and runs via Bitpay.
So if you own a webshop thats hosted by us you only need to create a Bitpay account and your done.
Though, my boss says the following:

What if only 2 or 3 customers want to  add Bitcoin to there shop?
We also need to give them support if something is wrong or if they need any help.
So I need to know how many customers would like to start accept Bitcoin before we just start offering this.
So if you can show me concrete numbers about Bitcoin. And you can show me alot of people in Belgium, The Netherlands and Germany and also maybe the rest of Europe are using Bitcoin alot.
Then probably we are gonna offer this to our clients.

Our company is gonna be worlds first.

So thats the story of how big this is.

Sorry for my English.

Thanks.

if your looking for some charts.. its limited because of anonymity, its hard to tell where people that use bitcoin actually live.. but here is probably as close as you can get to a chart showing numbers and locations. (warning: outdated, but useful as a guide to location ratio of the community)



it came from here http://bitcoinstatus.rowit.co.uk/

if you want to see it in a nice and impressive view here:
http://blockchain.info/nodes-globe

location based info should always be taken with a pinch of salt. but from reading forums the leader is USA followed by europe, which does have a big market for bitcoin businesses. unlike australia or asia south america or the UK which is small in comparison to the two top 'players',.

I agree with hazek's comments above, and would like to add that even if that was the right question to ask, the only way to know is to poll your customers.  That might give you some data you can use, but of course would take time and resources.

You're in the industry, so you should know what kinds of problems people have with the traditional methods.  Sell bitcoin as a way to avoid those pitfalls (account closures, clawbacks, etc).