"the numbers of Gaelic speakers in Scotland rose from just over 80,000 in 1960 to a little over 90,000 in 1990 - that's around 2.5% of the population "

Unfortunately you are exaggerating the number of Gaelic speakers Will. There were 80,000 in 1961 which increased to about 88000 in 1971 but that has steadily declined since by about a third to around 57000 on 2001. This is a little over 1% the population. There is some increase in Gaelic Medium education but worryingly the decline of Gaelic speaking in its heartland is still thought to be happening. The 90000 figure you give above (which is less than 2% of the population) is for the number of people who have 'some knowledge' of the language. That is it includes people who can read a bit of Gaelic or perhaps understand some spoken Gaelic etc.