ツ湘ウ窶ケツオ窶堙俄?堙ヲ窶堙ィ窶堙懌?堋キ窶堋ェツ、窶禿ウ窶堙債、ツ青ウ窶堋オ窶堋サ窶堋、窶堙??堋キツ。(1)窶堙債、ツ"20nenナ津」ツ"窶堙??堙坂?堙遺?堋ュツ、ツ"20窶扼窶堋?窶堋ス窶堙ィツ、20窶扼ツ債?ツ"窶堙嫁陳クツ渉ュ窶堋オ窶堙??堋オ窶堙懌?堙≫?堋ス窶堙??堋「窶堋、ナス窶凪?堙??堋キ窶堙ヲ窶堙仰。(will have dropped.)
[?] ナ陳クツ渉ュ窶堋ェツ鞘┐ツ々窶堙俄?ケN窶堋ア窶堙ゥ窶堙??堋「窶堋、ナス窶凪?堙??堋キツ。窶愿コ窶怒ナ津ェ窶堙娯?禿ウ窶堋ェ窶?窶佛督出窶藩??堙ゥ窶堋ッ窶堙?、窶堙懌?堋クツ渉ュ窶堋オ窶「テ渉更窶堋オ窶堙??堙?窶堙ァ窶堋「窶堙懌?堋キツ。窶堋サ窶堙ェ窶堙ァ窶堙娯?兒窶堋「窶「\ナ陳サ窶堙債、ツ"in 20 yearsツ"窶堋ェツ、ツ鞘┐ツ々窶堙俄?ケN窶堋ア窶堙≫?堙??愿≫?凖ィ窶堙娯?凖カ窶忸窶堙俄?愬セ窶傳窶堋キ窶堙ゥ窶堋ゥツ、20窶扼ツ債?窶堙俄?ケN窶堋ア窶堙ゥ窶ーツス窶堙ァ窶堋ゥ窶堙娯?敕アツ湘ュ窶堙可青ウナ?m窶堙?、窶ーテ闇?w窶廬窶堙盈oto-ni-shitaナ陳ゥツ静鞘?堙?窶堙ィ窶堙戸?ウツ湘帚?堙ー窶膿窶堋ヲ窶堙懌?堋キツ。ツ"within twenty yearsツ[20窶扼ヒ?遺?愿?ツ](2)ツ"窶堙債、ツ渉ュ窶堋オFlexible窶堙?、20窶扼窶楼ツ、窶堙懌?堋ス窶堙?0窶扼窶堙ヲ窶堙ィツ渉ュ窶堋オ窶楼ツ、窶堙?窶堋オ窶堋ゥ窶堋キ窶堙ゥ窶堙?、窶愿コ窶怒ナ津ェ窶堙?"窶堙ヲ窶堙ィ窶伉ス窶堋ュ窶堙坂?堙遺?堋「ツ"窶堋ゥ窶堙?窶堋オ窶堙ェ窶堙遺?堋「窶堙??堋「窶堋、ナス窶凪?堙俄?堙遺?堙ゥ窶堋ゥ窶堙?窶堋オ窶堙ェ窶堙懌?堋ケ窶堙アツ。
Thank you so much for explaining the sentences. Most of my translations would be incorrect, but I tried to translate them, because I couldn't read them easily.
My dictionary says "in" means ツ"ツ〜窶堙娯?堋、窶堋ソ窶堙可、ツ〜窶堙固?テ披?堙可" or ツ"ツ〜ナ津」窶堙可". It seems ツ"ツ〜ナ津」窶堙可" is used in the sentences that contain "will" and ツ"ツ〜窶堙娯?堋、窶堋ソ窶堙可、ツ〜窶堙固?テ披?堙可" are used in the sentences that don't contain "will".
In 20 years, this number is expected to drop to 100.
窶堋ア窶堙個絶?敘スナ。窶堙債、20窶扼窶堙娯?堋、窶堋ソ窶堙可(20窶扼窶堙固?テ披?堙可)100窶堙俄?ーツコgarutoツ考窶堋ヲ窶堙ァ窶堙ェ窶堙??堋「窶堙懌?堋キツ。
So, "in" means it happens gradually in this case... I think I understand.