def extract(start=2003,end=2011,year=None):
hours={}
hour=3600
days={}
day=24*hour
if year!=None:
start=year
end=year+1
for year in range(start,end):
infile='data/%d-rawtimes.csv' % year
print 'Extracting from %s' % infile
dts=fromfile(infile,year)
dt_objs=[row['value'] for row in dts]
for dt in dt_objs:
posix=int(dt.strftime('%s'))
# int truncates rather than rounds
increment(hours,int(posix/hour)*hour)
increment(days,int(posix/day)*day)
return {"hours":hours,"days":days}
