Python- Labeling items in a list by year -

basically writing program reads text file , places each line file list. file lists population, in thousands, of united states during years 1950 - 1990. file, however, not list year, need program label each population number year.

my assignment is:

"you write program (name analysis_population.py) read contents of file above list, , calculate , display:

• the average annual change in population during time period 1950 - 1990 (inclusive)

• the year greatest increase in population during time period 1950 - 1990 (inclusive)

• the year the smallest increase in population during time period 1950 - 1990 (inclusive)"

i have working except year label.

my code far follows:

year = 1950  open("uspopulation.txt", "r") f:     poplist = [line.strip() line in f]     poplist = [ int(x) x in poplist ] x in poplist:     year = year + 1  diff = [abs(j-i) i,j in zip(poplist, poplist[1:])] maxdiff = max(abs(x - y) (x, y) in zip(poplist[1:], poplist[:-1])) mindiff = min(abs(x - y) (x, y) in zip(poplist[1:], poplist[:-1]))  print("the average annual change in population during time period 1950 - 1990 is:\n",           (sum(diff)/len(diff)))  print("\nthe year greatest increase in population during time period 1950 - 1990 is:",           year, "-", year + 1, "with increase of", maxdiff, "people.")  mindiff = min(abs(x - y) (x, y) in zip(poplist[1:], poplist[:-1])) print("\nthe year smallest increase in population during time period 1950 - 1990 is:",           year, "-", year + 1, "with increase of", mindiff, "people.") 

the output is:

the average annual change in population during time period 1950 - 1990 is:  2443.875  year greatest increase in population during time period 1950 - 1990 is: 1991 - 1992 increase of 3185 people.  year smallest increase in population during time period 1950 - 1990 is: 1991 - 1992 increase of 1881 people. 

as can see, outputs same, incorrect year each time. correcting appreciated.

here link text file