That hymn is probably the most popular (traditional) English hymn for NO as well as EF, especially at the conclusion of Mass.
That certainly was true 50-60 years ago, but I doubt that it is today. The NPM survey from a few years ago ranked it no. 6.
http://www.catholicnews.com/data/stories/cns/0600465.htm
Keep in mind, however, that Noel asked about "most popular hymns" while CHG responded with a comment about "the most popular (traditional) English hymn."
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