How many Taiwanese live in China?

AmCham's 2007 White Paper calls on the people of Taiwan to:

Keep Families And Family Businesses Closer Together

Nearly 5% of Taiwan's people live and work in China – with the majority estimated to be between the ages of 24 and 50. It's time to make it easier for these people to be only hours away from spouses, children, senior family members, and business associates by being able to fly directly across the Taiwan Strait. This year is the 20th anniversary of the opening of travel from Taiwan to China. Few in 1987 would have guessed that it would take this long to allow regular, direct-route travel. Each year these restrictions needlessly hurt more and more Taiwan families – and family businesses. With regard to direct links, AmCham urges the government to listen to the pleas of its people – Just do it!

First of all, let's keep in mind that this is not up to the people of Taiwan, it's up to the government of China. The DPP government has wanted to negotiate with China about flights to and from China for years, but China insists that Taiwan first recognize the One China principle that Taiwan is part of China before it will discuss this issue. By disingenuously appealing to the people of Taiwan on this issue AmCham is inserting itself into Taiwanese politics on behalf of the KMT in an inappropriate and unseemly fashion.

Secondly, where does this figure of nearly five percent of Taiwanese living and working in Taiwan come from? That would be around 1.1 million Taiwanese living and working in China. But the pro-KMT and pro-direct links China Times puts this figure at 750,000, defined as Taiwanese who resided in China for more than 180 days. A difference of around 350,000 is extremely significant. What is AmCham's source for its five percent figure and how is residence defined. Inquiring minds want to know.