Frequency of blood types in different countries

Wikipedia lists the frequencies of different blood types in a number of countries across the globe. It's kind of interesting to see some of the regional differences. For instance, in China/Hong Kong and South Korea, it is extremely rare to have Rh- blood type. What might that mean for a person with Rh- blood who was traveling in those countries and needed a blood transfusion? Ireland has by far the largest percentage of O+ blood compared with any other country - it is notably higher than listed for the UK - what might that have to do with Ireland being an island nation? I wish there was data for some African countries and/or Southeast Asia...