Except I don't think it's true. : ( They probably mean compared with any given year in the last 3 decades.
This was funny: from https://oag.ca.gov/news/press-releases/attorney-general-bonta-issues-third-annual-labor-day-report
California Attorney General Rob Bonta today issued the third annual Labor Day Report highlighting the California Department of Justice’s (DOJ) ongoing efforts to empower workers in California and across the country. (Italics mine)
This from the state that enacted one of the biggest anti-worker and anti-democratic laws (that would permanently classified Uber/Lyft drivers as contractors and required a SEVEN-EIGHTHS (!!!) majority to over-ride). The measure (called prop 22) has been deemed unconstitional (at least in parts) by appelate courts and is currently in review by Calif Supreme Court.
I'd actually be interested in knowing figures for people in unions who have authorized strikes, since that might be a more complete figure for the increasing influence of unions. The Teamsters were completely ready to strike, but they didn't get to because they got everything they asked for, and that should count.
Teamsters didn't get everything they asked for. There are still two tiers (just a different set), for example. Bargaining was closed so we don't really know what initial bargaining demands were. And the reform movements were demanding $25/hour base pay, which they didn't get.
Teamsters were bragging about having day-1 strike pay (very rare, means they're flush) and didn't use their power to strike and get more.
UPS execs are very happy about the result.