Now let's discuss our second quarter results, in which we achieved a $1.54 in adjusted EPS, an 86% increase over Q2 of 2019, and adjusted EBITDA of $92 million, an increase of 62%.
Average paid worksite employees declined by just 1.8% from Q2 of 2019 compared to our forecast of 1% to 5% decline that took into account the impact of the COVID-19 pandemic on our clients and prospects.
Worksite employees paid from new client sales were approximately 20% above forecasted levels, driven by 15% increase in trained Business Performance Advisors and success in our mid-market segment.
Client retention held up at our historical high level of just over 99% during Q2.
So let's move on to gross profit, which increased by 27% over Q2 of 2019.
These credits totaled approximately $12 million and were accrued in the second quarter.
These deferrals and credits totaled approximately $45 million during Q2 and were reported as both a reduction to revenue and direct costs.
So in total, these two items reduced Q2 reported revenues by approximately $57 million and gross profit by approximately $12 million.
Second quarter operating expenses increased by 9% and included continued investments in our growth, including costs associated with the increase in the number of Business Performance Advisors.
Our effective tax rate in Q2 came in at 27%, and we expect a similar rate over both the latter half of this year and for the full-year 2020.
Adjusted cash totaled $269 million at June 30, up from $108 million at December 31, 2019, while borrowings totaled $370 million at the end of Q2, up from $270 million at December 31, 2019.
Over the first half of this year, we have repurchased 879,000 shares of stock at a cost of $61 million, paid $31 million in cash dividends and invested $39 million in capital expenditures.
In more than 30 years, I've never seen a quarter where clients experienced more of what we are designed to offer in such a compressed time period.
On our last call, we indicated our objective in new account sales operating in this virtual selling environment would be to fall within a range of 60% to 80% of our original 2020 pre-COVID sales budget.
Our entire sales organization, both core and mid-market performed remarkably well, achieving total booked sales above 70% of our original 2020 pre-COVID sales budget and in the higher end of our own revised targeted range.
During the quarter, we worked with vendors and negotiated $12 million in fee reductions to pass along to clients.
Now in the second quarter, layoffs due to COVID drove a 6% reduction in paid worksite employees from March, reaching a low point at the end of May.
Now since then, we've recovered approximately 40% of this reduction, primarily due to the return to work of just over 50% of furloughed employees.
At the same time, approximately 17% of furloughed or temporarily laid off employees have been reclassified to permanent layoffs, so the number of potential rehires has been reduced by two-thirds.
Our full year guidance for 2020 implies a range of minus 1% to minus 3% unit growth in paid worksite employees.
We expect a range of adjusted EBITDA growth that straddles to the level we achieved last year at minus 6% to plus 2%.
Based upon the details that Paul just shared on our expected worksite employee levels, we are now forecasting a 1% to 3% decrease in the average number of paid worksite employees for the full-year 2020.
This is a substantial improvement over our previous guidance of a 1% to 6% decrease and reflects the more favorable starting point for the second half of the year.
For the full-year 2020, we are raising our earnings guidance and now forecasting adjusted EBITDA of $235 million to $255 million, ranging from a decrease of 6% to an increase of 2% when compared to 2019.
This compares to our previous guidance, which ranged from a decrease of 14% to flat with 2019.
Finally, our updated earnings guidance assumes a reduction of approximately $3 million in net interest income from our previous guidance due to the recent decline in interest rates.
As for the full year 2020 adjusted EPS, we are now forecasting a range of $3.67 to $4.04, up from our previous guidance of $3.19 to $3.86.
Now as for Q3, we are forecasting average paid worksite employees in a range of 227,500 to 230,000, which is a small sequential increase over Q2.
We are forecasting adjusted EBITDA in a range of $29 million to $38 million and adjusted earnings per share in a range of $0.37 to $0.54.

Summary:
Now let's discuss our second quarter results, in which we achieved a $1.54 in adjusted EPS, an 86% increase over Q2 of 2019, and adjusted EBITDA of $92 million, an increase of 62%.
Our full year guidance for 2020 implies a range of minus 1% to minus 3% unit growth in paid worksite employees.
We are forecasting adjusted EBITDA in a range of $29 million to $38 million and adjusted earnings per share in a range of $0.37 to $0.54.