The position and status of the individual continues to change with progress of the country. That is why, the ratio of social mobility is high in developed countries like U.S.A, UK and Switzerland. On the other hand in undeveloped countries this ratio is normally lower enough. e.g. as compare to past, due to economic development of the country the Rural Urban migration has increased a lot.
The people to struggle to realize this desire. e.g. that is why in our country the people migrate from Rural setting to Urban and even to abroad for this purpose.
The people can easily go to any country which leads the trend of Social Mobility.