Based on NASA GISS GISTEMP data.
In the animation, years from 1880 to 2017 are divided into two groups: years that were colder and years that were warmer than the 1951-1980 average. Years are then added as circles into the group where it belongs. The size and color of the circles represent the temperature anomaly. The larger the circle and the stronger the color the higher/lower the temperature anomaly was.
Research scientist at Finnish Meteorological Institute