The chart below shows how the population of three counties of Oregon changed during the years. Describe the chart.

The line graph illustrates how the population varied in three counties (Columbia, yamhill, Washington) between 1950 and 2000. Units are measured in thousands. Overall, it can be seen that the population followed an upward trend during the given period. Additionally, Washington remained the most populated city as opposed to Columbia which recorded the lowest rate. In 1940, 75000 people lived in Washington, more than the double of that of Yamhill( 30000) and Columbia (approximately 250000). By 1970 Washington saw a dramatic increase of about 60000, following another significant growth by 2000 when the number of inhabitants peaked at marginally above 240000. Columbia and Yamhill experienced similar patters of growing gradually and then witnessing a rapid growth. By 1970, Columbia a slight increase in population of about 10000 and then peaked in 2000 with merely above 75000. Similarly, Yamhill hit 45000 in 1970 and quickly escalated reaching 90000 by the end of the period