import urllib.request, shelve

url= 'http://nancymcohen.com/csci133/cpiai.txt'
file = urllib.request.urlopen(url)
lines = file.readlines()
file.close()

cpi = {}
for line in lines:
    items = line.decode().split()
    if len(items)>0 and items[0].isdigit():
        cpi[int(items[0])]=[float(item) for item in items[:13]]

shelf = shelve.open('cpi')
shelf['cpi']= cpi
shelf.close()

def pctIncrease(begin, end):
    return100*(end/begin-1)

print('    Percent increase in CPI')
print('       (Jan - Jan)')
print('    1 year 5 years 10 years')

pattern1 = '{0:d}{1:6.1f}'
pattern2 = '{0:9.1f}'

for year in range(1914, 2009):
    currentCPI = cpi[year][1]
    pct = pctIncrease(cpi[year-1][1], currentCPI)
    print(pattern1.format(year,pct), end='')
    if year-5>= 1913:
        pct= pctIncrease(cpi[year-5][1], currentCPI)