According to a recent survey conducted in Taiwan, comparing to 12 years ago, more people in Taiwan consider themselves Taiwanese, rather than Chinese.
The items in the chart are, from top to bottom:
You consider yourself a Taiwanese; You consider yourself a Taiwanese and a Chinese; You consider yourself a Chinese; A Taiwanese is a Chinese
The orange bar represents numbers in 1997 while the blue bars represents numbers in 2009. Taiwan calendar starts in 1911, when the Republic of China (ROC) was founded in Nanjing. It is noted that 'Chinese' as quoted is not the same as citizen of the People's Republic of China.
The rapid changing self identity landscape can be read as a result of political wrangling between two parties. The KMD who historically rely on people originally from the mainland, while the PPD who make itself known by pushing towards an independent country detached from the mainland. Taiwan is one of few places in the world that in very recent years to create an ethic group purely by residency. Both parties count on votes of people who do not agree on the other party's ethnic policy. During the ruling of PPD from 2000 to 2008, more Taiwan people are steered by the politics towards labeling themselves mainstream, Taiwanese.
On the other hand, for many years since the overturn of ROC in 1949 in mainland, people in Taiwan has been fed of the idea that people in the mainland are suffering from the communist ruling, and that people in Taiwan had the moral obligation to rescue folks in mainland. Taiwan had been actively pursuing military assault of mainland until it's obviously that the mainland gained upper hand. Subsequently Taiwan has been worried about being invaded by the mainland, and increasingly sees the mainland a threat. Declaring independence leaves the mainland with one less reason to pursue the unification by force.
The population composition is changing too. Many people originally from mainland before 1949 are dying. In general people from mainland have better education as well as means and ways. Their offspring are more likely to have left Taiwan to US or Japan.