All Jews who aren't completely assimilated. So rather just ask how many Jews are there.
Purim, like the Passover Seder, Yom Kippur, circumcision, bar mitzvah and certain other things, is one of those parts of Judaism observed by all Jews who are even minimally aware of their heritage.
Yes, all branches of Judaism celebrate Purim.
Yes. Like Yom Kippur, circumcision, reciting of Kaddish, and the Passover Seder, Hanukkah is observed by all Jews.
All over the world, in their homes and in synagogues.
Almost all Jews celebrate Hanukkah.
All Orthadox Jews Celebrate Chanukkah, almost all non-Orthodox Jews also celebrate it as well.
Purim is not one of the main holidays - it's was instituted nearly 1000 years after the main holidays were given to Moses on Mount Sinai. Purim celebrates the survival of the Jews in Persia in the 5th century BCE. Read all about Purim at http://www.answers.com/topic/purim
there are many jewish holidays including pesach, sukkos, shavuos, channukkah, purim, and rosh hashana. they all celebrate different things.
Irish Jews celebrate Passover the same way as Jews all over the world.
The same as Jews all over the world.
The same way Jews in all other countries do.
The same way that all other Jews observe Pesach (Passover).
Yes, Jews celebrate Hanukkah in many different countries.
Jews celebrate Hanukkah all over the world.
Slightly less than the percentage of Jews in each country (since Hanukkah is a Jewish festival and most but not all Jews celebrate it).