Difference between group and ungrouped data?

Ungrouped data is the raw data, and correct statistics such as the mean and standard deviations can be determined. Ungrouped data is usually the starting point of analyses. Grouped data means there is less data to work with and my statistics will be approximate. But we work with grouped data all the time, and so long as the interval is not too big, there's no problem. It is frequently necessary to group the data to observe trends. I will give you an example: If I say there have been 10 million accidents in the last 20 years and 5 million in the interval from 20 years to 40 years ago, it doesn't tell me much. But if I present data of the number of accidents in the last forty years, by year, this is grouped data given in a meaningful manner.