The labour income share is calculated as the ratio of total labour compensation to GDP. The labour component of income earned by the self-employed is not separately identifiable. To estimate this, a simple assumption is used, namely that the self-employed and employees earn the same average hourly compensation for labour. Total labour compensation is therefore calculated as compensation of employees multiplied by the number of hours worked by all persons (employees and self-employed), divided by the hours worked by employees.
For Chile, Japan, Korea and the United States, as total hours worked by main ISIC Rev.4 economic activity are not available, the number of persons employed by sector is used, and so, Figure 5.4 necessarily assumes that the average labour compensation of the self-employed is the same as that of employees for these countries.
Note that the decline in labour income shares can be decomposed into a labour productivity component and a real labour compensation per hour component, when labour compensation costs are adjusted for inflation using the same price index as that used to deflate value added. In other words, declining labour income shares are consistent with productivity-wage decoupling.
Information on data for Israel: http://dx.doi.org/10.1787/888932315602.