#154 is a non-breaking space.
The upper half of KOI8-R code table: 80h - FFh
See also Unicode style mapfile for KOI8-R, Registration of a Cyrillic Character Set, UTF-8 codes for KOI8-R encoding, KOI8-R description in RFC 1345 format, KOI8-R description in ISO 9945-2 charmap format.