The bottom line is it cannot be determined. The reasoning is we can only discover how many topics there are for Halloween as the Key Word at the Topic Tree & those Hubs. There are a total of 3,308 as posted at the Topic Tree on 08/08/15. That offers questioning how many Hubs were published after that.
Now for TMI . . . an Adventure
‘Please take note’ following is a topical discussion. “A very important 'Key to a Hub's Success” is with a Search. At task is SEO principals & Techniques. Some are Title, Keywords, Summary, & today the URL with its focus on Topic Announced at the Forum and recent Blog It is important now to classify Hubs with the Best Topic. One place for discovering Topics with their hubs is the Topic Tree. Easily using a Browser Feature for ‘Find’ those may be made.
The Hub Topic Tree may be explored → http://hubpages.com/topics/tree
More TMI . . . my Playtime at the Topic Tree
The Hub count discovered is all are in the 1st level Subtopic – Halloween, of The Main Topic ‘Holidays and Celebrations’. I did not ‘Find’ any at other locations. Bear in mind the Main Topic is also a topic with its Hubs as so it is with Subtopics & so forth.
Holidays and Celebrations for all Hubs are 25,450. As a topic there is 10,151 Hubs. Does any Halloween Hubs exist there? I dun’no . . . That said the topics for Halloween and their Hub Count is 3,308.
Notes: Holidays and Celebrations is 3.2% of all Hubs at that time (804,409)
** Halloween is 3.2% of the Main Topic and is ranked #1 as its Subtopic.
** It is followed by Christmas, then Birthdays and Celebrations with their subtopics.
The Topic Structure with Hub Count is . . .
Main Topic; Holidays and Celebrations (All Hubs 25,450) – 10,151 as a topic
1st Level Subtopic (All Hubs 3,308); Halloween – 2,191 as a topic
2nd Level Subtopic – Halloween around the world – 15
2nd Level Subtopic (All Hubs = 740) – Halloween Costumes – 579 as a topic
3rd Level Subtopic – Halloween Costumes for Children – 55
3rd Level Subtopic – Halloween Costumes for Infants – 15
3rd Level Subtopic – Halloween Costumes for Men – 19
3rd Level Subtopic – Halloween Costumes for Women – 72
2nd Level Subtopic – Halloween Decorations – 132
2nd Level Subtopic – Halloween Party Ideas – 117
2nd Level Subtopic – Haunted Houses and Attractions – 47
2nd Level Subtopic – History of Halloween – 32
2nd Level Subtopic – Religious Perspective on Halloween – 7
2nd Level Subtopic – Trick-or-Treating – 27