Health Insurance Coverage

I got a survey about health insurance coverage on www.census.gov website.

The number of people with health insurance coverage increased from 245.9 million to 247.3 million (2004- 2005); however, the percentage of people without health insurance coverage increased from 15.6 percent ( 2004) to 15.9 percent (2005).
In fact, people who are covered by employment based health insurance decrease from 59.8 percent to 59.5 percent between 2004 and 2005.

I do not know how health insurance is important because in my country, everyone has it.
And also I wonder why people with insurance increase though, there are some people without insurance with also increasing.