I would imagine it was dependent on the fashion and what was selling at the time.
Early '70s into the '80s, browns were popular, so the range which came to be called Tortoiseshell at IoWSG (and was Earthtones at Mdina) was the one that sold most and was made the most, but there are not that many attenuated bottles.
Pink and blue swirls was an official range, but it is still very scarce, Seaward was an official range, but very short lived - it didn't sell as well as Tortoiseshell, so all of it is pretty scarce. Attenuated bottles are very thin on the ground. I have one, Gary (a serious collector who isn't a member here) has one, I remember him finding it, he was dancing around the fair in jubilation. I'm sure John has at least one. I've seen one other.
Aurene was a popular range, and is possibly the most commonly found design in attenuated bottles, but even they are still not common and make good money.
Plain pink, or plain blue swirls have been seen; there are a few (but probably under 10) of each "out there" which are known about.
We've not seen a white one before.
All early IoWSG attenuated bottles are fairly scarce and desirable. You've got yourself something seriously unusual
within that.
We really don't know how many may have been made, Anne. But we really don't think it would have been many.
I'd risk saying they could probably be counted on fingers.
Everything was still quite experimental in the early days.
My Seaward is only vibrant in sunshine. Otherwise, it's a fairly dark thing.