Finishing off the Agatha Christie short stories

According to my records, although I have completed reading the Agatha Christie novels, I still have a number of short stories to go.

First of all I need to check out these collections:

• 1939 The Regatta Mystery and Other Stories (nine short stories - US only)
• 1948 The Witness for the Prosecution and Other Stories (eleven short stories - US only)
• 1950 Three Blind Mice and Other Stories (nine short stories - US only)
• 1960 The Adventure of the Christmas Pudding (six short stories - UK only)
• 1961 Double Sin and Other Stories (eight short stories - US only)
• 1971 The Golden Ball and Other Stories (fifteen short stories - US only)
• 1974 Poirot's Early Cases (eighteen short stories, also known as Hercule Poirot's Early Cases in the US)

However many of the short stories published in these collections were also published in other collections and I have actually read them.
So I have begun tracking the collections above through my local library network and finding the elusive few that I haven't yet read. The problem is compounded by the fact that some were also published under other titles according to whether they were published in the US or UK, or whether they were modified and then re-published.
So, a bit of tedious housekeeping ahead.

Currently I have 143 short stories on my list, but I am not sure how many there are in total.
Has anybody come across a number? An article on Wikipedia suggests 153, but I don't think that includes any recently "found".