With no explanation, label each line with "location-GPE", "O", "art-broadcastprogram", "art-film", "art-music", "art-other", "art-painting", "art-writtenart", "building-airport" or "building-hospital" preceded by ":".
Since
fortification
began
,
the
rate
of
neural
tube
defects
has
decreased
by
approximately
one-third
in
the
US
.
Since:O
fortification:O
began:O
,:O
the:O
rate:O
of:O
neural:O
tube:O
defects:O
has:O
decreased:O
by:O
approximately:O
one-third:O
in:O
the:O
US:location-GPE
.:O