Question for Wendybeth

[Cadaverous Pallor]

I figure others may have hard-of-hearing people in their lives but I know for sure Wendybeth can help me.

I'm looking into Assisted Listening Devices for the hard-of-hearing in the new library conference and meeting rooms. One choice we have to make is to get either normal earbuds/headphones or get what's called the neckloop. The neckloop works with hearing aids that are telecoil-equipped. That way a person with a hearing aid can use the ALD as well as their hearing aid.

I was wondering - How common are telecoil-equipped hearing aids? Is it standard on most hearing aids, or an expensive add-on that most people don't get? If you needed to hazard a guess - what percentage of hearing aids has this technology?

Thanks.