Colorado does not currently have an estate tax, death tax or inheritance tax. Residents and citizens of Colorado, as well as non-resident, non-citizens who own property in Colorado, are subject to the United States Estate Tax.
In 2004, only 251 people domiciled in Colorado paid estate taxes. The number for 2006 will probably be smaller, as the amount that can pass tax free to heirs has increased this year. In the most recent year for which statistics are available, 2003, there were 29,506 deaths in Colorado See also here, a figure which has been gradually increasing from year to year as Colorado's population has increased.
Thus, less than one percent of decendent's estates in Colorado are subject to the federal estate tax.