Pre 1980 Illegals were an insignificant number that were pretty well confined to doing stoop labor in the SW.
By 1990 Illegals were making their presence known in construction, manufacturing and in residential service work.
1990's also coincides with a decline in Trade Union market share and bargaining power.
It was about this time that the Democrat led Washington State Dept of Labor & Industries stopped sending compliance officers around to check our credentials and to be sure that everyone [their fellow US Citizens] were getting paid the prevailing wage.
By now the agenda to look the other way and allow the Illegal Alien invasion to shift into high gear was obvious.