我国每年总人口数量、男性人口、女性人口、城镇人口以及乡村人口的数量都在发生变化，国家数据统计了近30年的人口数据，根据以下数据，绘制折线图，观察一下我国的人口变化趋势吧

1991~2020年人口数据如下：

# 1991~2020
years = pd.date_range('19911231','20201231',freq='Y')

# 年末总人口(万人)
population_total = np.array([115823,117171,118517,119850,121121,122389,123626,124761,125786,126743,127627,128453,129227,129988,130756,131448,132129,132802,133450,134091,134916,135922,136726,137646,138326,139232,140011,140541,141008,141178])

# 男性人口(万人)
male_total = np.array([59466,59811,60472,61246,61808,62200,63131,63940,64692,65437,65672,66115,66556,66976,67375,67728,68048,68357,68647,68748,69161,69660,70063,70522,70857,71307,71650,71864,72039,72334])

# 女性人口(万人)
female_total = np.array([56357,57360,58045,58604,59313,60189,60495,60821,61094,61306,61955,62338,62671,63012,63381,63720,64081,64445,64803,65343,65755,66262,66663,67124,67469,67925,68361,68677,68969,68844])

# 城镇人口(万人))
town_popu = np.array([31203,32175,33173,34169,35174,37304,39449,41608,43748,45906,48064,50212,52376,54283,56212,58288,60633,62403,64512,66978,69927,72175,74502,76738,79302,81924,84343,86433,88426,90199])

# 乡村人口(万人)
country_popu = np.array([84620,84996,85344,85681,85947,85085,84177,83153,82038,80837,79563,78241,76851,75705,74544,73160,71496,70399,68938,67113,64989,63747,62224,60908,59024,57308,55668,54108,52582,50979])

以下是小慕同学的效果图，可以参考哦~