According to the Encyclopedia Britannica Online:
In reply to:
Although Ireland was invaded and colonized within historical times by Celts, Norsemen, Normans, English, and Scots, there are no corresponding ethnic distinctions. Ethnic and racial minorities make up less than 5 percent of the population. However, immigration from Europe, Africa, and Asia was significant in the last two decades of the 20th century. Although they are small in number, the nomadic Travellers (“Tinkers”) are perhaps the most prominent ethnic minority group.
That doesn't exactly sound like Detroit, New York, or Miami. It looks like, except for thte Travellers, Ireland was quite lilly-white 20 years ago; now it's kind of like southern New Hampshire.