I can't answer directly to the figures, but I do know a lot of blind people don't read braille. That said, those figures are probably relative to people classified as blind in law, some of which can still have some capacity to read visually (large print, powerful lenses, etc).

In the UK there are alternatives to braille like the $1 which is claimed to be easier to learn for those who already know the Latin script in print, so my understanding is many adults are taught that instead.

Further, as you say, there's a lot more ways to access information now. Not only screen readers, but things like audiobooks, $1, etc. Some people think braille is obsolete, too expensive, slow, etc (I would strongly disagree, but some people do).

I've also heard of cases where students could benefit from braille but they don't want to be stigmatised as blind, or their teachers don't want to, resulting in them using alternatives like large print, magnification etc, sometimes with not so good results.

10% is accurate here in the US. Read more about the [Braille literacy crisis in America]
(https://nfb.org/images/nfb/publications/bm/bm09/bm0905/bm090504.htm) here.

In my opinion, some of the biggest issues are:

Among children:

- Braille is relatively expensive to produce, requires relatively expensive equipment, and requires a teacher who is competent with braille (which there is a shortage of.) Schools have a financial incentive to discourage braille use.

- Children who are "just" legally blind are often encouraged by schools and/or their parents to rely on their remaining vision under the (highly misguided, IMO) mindset that they aren't "blind enough" to need it.

- Parents or teachers might fear stigma
about braille reading, and parents can be in denial about the extent of their child's visual impairment.

- For more severely blind children, "text to speech is enough" is an unfortunately common belief.

- There are a lot of misconceptions about braille being very hard to learn or use, being impractical or too slow, or that children with even minor developmental disabilities couldn't possibly ever use braille.

- Legally, schools [must]
(https://nfb.org/braille-and-vi-students) provide braille for children with substantial visual impairments. In practice, many parents either do not know, do not exercise, or are denied their child's rights.

Among adults:

- The cost of braille equipment, such as a refreshable braille display to use with a computer or phone, is cost prohibitive to many blind people (especially those who can't or don't want to receive devices through govt. rehab services.) This is a situation that is very soon changing with the introduction of a [20 cell, $500 braille display]
(http://www.aph.org/research/orbit-reader-20-details/) a severe drop from the approximate $2000 that comparably sized braille displays roughly average.

- Adults who have been blind many years may feel they've gotten along just fine without braille up until now, so why change things?

- Adults who are newly blind, especially later in life, receive many messages that braille is difficult or impossible to learn as an adult, that it is cumbersome and outdated, and why should you bother when TTS is everywhere?

- Adults often carry the same mental hangups about braille being for people who are "more disabled" than they are, that using braille will make them look strange, etc.

- There is a shortage of qualified, sufficient braille instruction for adults, especially among adults that don't live near major cities.

The reason for it everywhere is that it is helpful and needed for the ones of us, who read even a little bit. before working with a braille teacher I self taught the numbers, and the letters s (ie for stairs) m (for know which was the men's restroom) and w (to know which was the women's restroom). I became blind at 18, actually working with a Braille teacher started less than a month ago, I am already comfortable with grade one the letters, numbers and punctuation. As much as I wish I was the norm, I am not, not because Braille is so hard, but because people think it is.
The other problem is people don't seem to get Braille is useful to those like myself with some vision still.
The other reason for it is a lack of Braille books and access to Braille tech. (I can buy a copy of window eyes if I choose to for under 500$, I can download NDVA for free) The same can't be said for Braille.

In Canada, 90% of people with vision loss have some usable sight. And many of the people who lose their vision is at an older age, so they are much less likely to learn braille than someone who lost their vision when they were younger.