1 # Allowance for leap seconds added to each time zone file.
   2 
   3 # This file is in the public domain.
   4 
   5 # This file is generated automatically from the data in the public-domain
   6 # leap-seconds.list file, which can be copied from
   7 # <ftp://ftp.nist.gov/pub/time/leap-seconds.list>
   8 # or <ftp://ftp.boulder.nist.gov/pub/time/leap-seconds.list>
   9 # or <ftp://tycho.usno.navy.mil/pub/ntp/leap-seconds.list>.
  10 # For more about leap-seconds.list, please see
  11 # The NTP Timescale and Leap Seconds
  12 # <https://www.eecis.udel.edu/~mills/leap.html>.
  13 
  14 # The International Earth Rotation and Reference Systems Service
  15 # periodically uses leap seconds to keep UTC to within 0.9 s of UT1
  16 # (which measures the true angular orientation of the earth in space)
  17 # and publishes leap second data in a copyrighted file
  18 # <https://hpiers.obspm.fr/iers/bul/bulc/Leap_Second.dat>.
  19 # See: Levine J. Coordinated Universal Time and the leap second.
  20 # URSI Radio Sci Bull. 2016;89(4):30-6. doi:10.23919/URSIRSB.2016.7909995
  21 # <https://ieeexplore.ieee.org/document/7909995>.
  22 
  23 # There were no leap seconds before 1972, because the official mechanism
  24 # accounting for the discrepancy between atomic time and the earth's rotation
  25 # did not exist.  The first ("1 Jan 1972") data line in leap-seconds.list
  26 # does not denote a leap second; it denotes the start of the current definition
  27 # of UTC.
  28 
  29 # The correction (+ or -) is made at the given time, so lines
  30 # will typically look like:
  31 #       Leap    YEAR    MON     DAY     23:59:60        +       R/S
  32 # or
  33 #       Leap    YEAR    MON     DAY     23:59:59        -       R/S
  34 
  35 # If the leap second is Rolling (R) the given time is local time (unused here).
  36 Leap    1972    Jun     30      23:59:60        +       S
  37 Leap    1972    Dec     31      23:59:60        +       S
  38 Leap    1973    Dec     31      23:59:60        +       S
  39 Leap    1974    Dec     31      23:59:60        +       S
  40 Leap    1975    Dec     31      23:59:60        +       S
  41 Leap    1976    Dec     31      23:59:60        +       S
  42 Leap    1977    Dec     31      23:59:60        +       S
  43 Leap    1978    Dec     31      23:59:60        +       S
  44 Leap    1979    Dec     31      23:59:60        +       S
  45 Leap    1981    Jun     30      23:59:60        +       S
  46 Leap    1982    Jun     30      23:59:60        +       S
  47 Leap    1983    Jun     30      23:59:60        +       S
  48 Leap    1985    Jun     30      23:59:60        +       S
  49 Leap    1987    Dec     31      23:59:60        +       S
  50 Leap    1989    Dec     31      23:59:60        +       S
  51 Leap    1990    Dec     31      23:59:60        +       S
  52 Leap    1992    Jun     30      23:59:60        +       S
  53 Leap    1993    Jun     30      23:59:60        +       S
  54 Leap    1994    Jun     30      23:59:60        +       S
  55 Leap    1995    Dec     31      23:59:60        +       S
  56 Leap    1997    Jun     30      23:59:60        +       S
  57 Leap    1998    Dec     31      23:59:60        +       S
  58 Leap    2005    Dec     31      23:59:60        +       S
  59 Leap    2008    Dec     31      23:59:60        +       S
  60 Leap    2012    Jun     30      23:59:60        +       S
  61 Leap    2015    Jun     30      23:59:60        +       S
  62 Leap    2016    Dec     31      23:59:60        +       S
  63 
  64 # POSIX timestamps for the data in this file:
  65 #updated 1467936000
  66 #expires 1561680000
  67 
  68 #       Updated through IERS Bulletin C56
  69 #       File expires on:  28 June 2019