I18n::MissingTranslationData, translation missing: ja, number, human, storage_units, format

While translating the application in Japanese language, I got following error:

I18n::MissingTranslationData in Campaigns#campaign_upload

Showing C:/projects/demoapp/app/views/campaigns/_update_uploads.html.erb where line #20 raised:

translation missing: ja, number, human, storage_units, format

For line:
<%=number_to_human_size(asset.attachment_file_size)%>

Error displays that some translation is missing for ja, number, human, storage_units, format.

To fix the error:
 
Changed the code in view to include locale params:

<%=number_to_human_size(asset.attachment_file_size, :locale=>I18n.locale)%>

Added following codes in config\locales\ja.yml file :

ja:
 number:   
    format:
      separator: "."
      delimiter: ","
      precision: 3
      significant: false
      strip_insignificant_zeros: false   

    # Used in number_to_human_size() and number_to_human()
    human:
      format:
        delimiter: ""
        precision: 3
        significant: true
        strip_insignificant_zeros: true

      # Used in number_to_human_size()
      storage_units:
        format: "%n %u"
        units:
          byte:
            one: "Byte"
            other: "Bytes"
          kb: "KB"
          mb: "MB"
          gb: "GB"
          tb: "TB"

      # Used in number_to_human()
      decimal_units:
        format: "%n %u"
        units:
          # femto: Quadrillionth
          # pico: Trillionth
          # nano: Billionth
          # micro: Millionth
          # mili: Thousandth
          # centi: Hundredth
          # deci: Tenth
          unit: ""
          # ten:
          # one: Ten
          # other: Tens
          # hundred: Hundred
          thousand: Thousand
          million: Million
          billion: Billion
          trillion: Trillion
          quadrillion: Quadrillion

Although the above codes are in English language, you can get the above code in  Japanese or any other languages also, which will fix number_to_human_size  error..