Increased since when? 1940s? 60s? 80s? If so, then yes that would be correct. I was talking about 2001-2011 and therefore Garrett would be dispproved by National Assembly data, additonally my students research this as part of my course annually so I can give you plenty of sources if you truly are interested. Pm me.
I responded to your original posting on this as I did my research degree on it and discuss/analyse and interpret it as part of my every day vocation. What you say is correct at large but it is a very simplistic view of things. Ofc the Welsh recognised themselves as being alien to the English but when the Vikings hit we were no more than tribes folk and this largely remained up until our Conquest by the English. We did not have an identiy of being "Welsh" as in "Wales", and Llywelyn ap Gruffydd, known as the Last Prince of Wales, was self-proclaimed and self-indulgent at best. His motivation were fuelled by ambition for the House of Aberffraw and the region of Gwynedd, not Wales as a country. There was no identity of being a one people, under one banner of one country, and claims to the contrary are no more than patriotic romanticism. Ironically, the Tudors did more for our identity as a Welsh people than Llywelyn or Owain Glyndwr, and that was inspite of their efforts not because of them.