Density - (noun)
Trade union density is an indicator of unionisation in relation to the size of the available labour force. It refers to the proportion of employees in a country that are members of a trade union.
Source: Adapted from EuroFound
Example of Use: Levels of union density vary widely across the 27 EU states plus Norway, from around 70% in Finland, Sweden and Denmark to 8% in France. However, density is not the only indication of unions’ capacity to mobilise workers. In most countries union membership has been falling in recent years, and, even where it is growing, it has not generally kept pace with the rise in the numbers employed.