The given line graphs illustrate the percentage of households with electrical appliances and the time taken to do housework during the years between 1920 and 2019. We can infer from the graphs that the number of 
hours
 spent in a Use synonyms
week
 doing housework had decreased steadily Use synonyms
due to
 the increased use of electrical appliances in houses had increased dramatically throughout the given timeline.
In the Linking Words
year
 1920, none of the houses had a refrigerator, which significantly became popular in 1940 with nearly every second household having one, and by the Use synonyms
year
 1980, almost every household had a refrigerator. Use synonyms
Similarly
, every home had a vacuum cleaner by the Linking Words
year
 2000, which earlier in 1920 was at only 30%. 40% of the households at the beginning of the timeline had washing machines, which increased linearly until 1960, with a small drop of nearly 10% during the period between 1960 and 1980, and Use synonyms
subsequently
 continued to increase Linking Words
further
.
In 1920, nearly 50 Linking Words
hours
 of time work was spent on housework every Use synonyms
week
 by an individual household, which significantly declined until the Use synonyms
year
 1960, at 20 Use synonyms
hours
 a Use synonyms
week
 with the increase in the use of electrical appliances. Use synonyms
Furthermore
, in the later years, the time spent continued to decrease steadily, which reached  a lowest at 10 Linking Words
hours
 a Use synonyms
week
 by the Use synonyms
year
 2019.Use synonyms