What has determined longer run trends in Public Housing tenants' employment participation 1982-2002?

In the twenty years 1982-2002 the employment participation rate of all working age persons has increased. Since 1982 there has been a particularly sharp increase in participation rates among working age residing in households that are buying their home. On the other hand employment participation rates among female public housing tenants have remained low. Among males there are small declines in the employment participation rate of homeowners and private rental tenants, but a sharp decline among male public renters over the same time period.