Temporary and contract staffing employment was 2.2% higher for the week of May 7 to May 13 than the same week last year, according to the American Staffing Association’s staffing index. It marked the fastest rate of year-over-year growth for this particular week in four years.

Month-over-month, the ASA Staffing Index edged down 0.1% but remained at a rounded reading of 97 for the week. This marks the best reading for this particular week since the start of the ASA Staffing Index in 2006 and continues a streak that began in April of record-high readings for the comparable week.

The index’s four-week moving average edged up for the ninth consecutive period to a rounded figure of 97, also a historically high value for the same period. Year over year, the four-week average rose 2.4%, its fastest pace since 2014.