A graph of the frequency of words based on chance, fate, fortune, and luck may be found here.  “Fortune” occurs most frequently as “fortunately”.

• 2.030 Fortunately the road went over an ancient stone bridge,
• 5.004 nor fortunately had the goblins noticed it,
• 5.034 Fortunately he had once heard something rather like this before,
• 5.039 Unfortunately for Gollum
• 7.022 nor rug, cape, tippet, muff, nor any other such unfortunate word!
• 8.108 fortunately on to leaves,
• 8.145 he began to wonder what had become of his unfortunate friends.
• 9.030 and fortunately not far from the cellars.
• 10.003 that he was very fortunate
• 12.079 It was an unfortunate remark,
• 16.026 which fortunately I believe I have kept.’
• 18.031 May it bring good fortune to all his folk that dwell here after!’