Thank you, Julie, and hello, everyone. Thanks for joining the call. We know it's short notice, but we think it's important to share our strong Q4 performance with you as soon as possible, particularly given this crazy time that we're in. We know, as it relates to COVID-19, this is a trying time. And in times like these, our most important focus is on our people and their families. In regard to everyone's health and well-being, weeks ago, we implemented common sense protocols, including putting restrictions on nonessential travel, supporting work-from-home initiatives and changing the format of our annual user conference to online only. Our thoughts are certainly with everyone who's affected at this time.
I'm going to keep my section short and sweet. I want to make -- take a -- I want to take a more reflective view and highlight the progress we have made since we became a public company, and then Bruce will cover this quarter's details. So this is our seventh reported quarter as a public company. In the last 7 quarters alone, we have made significant progress on a number of metrics.
Number one, our year-over-year subscription revenue growth has averaged 28% and has never been below 24% for any quarter. Number two, our subscription gross margins have improved from 71% when we went public to 77% today. Number three, our gross retention rate has improved from 82% to 91% this quarter. Number four, our contracted annualized recurring revenue is now over $160 million, a size and scale that gives us the ability to get to cash flow positive quickly if we need to. Number five, our customers under multiyear contracts have increased from 38% of our customer base when we went public to 55% today.
Number six, over that same time period, our operating expenses have decreased from $55 million per quarter to $53 million per quarter, despite our growth in recurring revenue. Number seven, we have decreased our quarterly cash burn from $36 million a quarter to now $15 million. And lastly, number eight, we've been able to accomplish all of this with the same headcount level we had about 4 years ago, and we still have sufficient capacity to continue to deliver significant value to our customers, also with an ample amount of cash to run our business however we need to, in whatever environment we are in.
I'm very pleased with these accomplishments in this past quarter, including signing one of the world's largest companies, Amazon, as a customer, and I look forward to continuing to execute well against this large market opportunity before us. The path to achieving a cash flow positive position with the cash on our balance sheet has become clear every quarter.
And with that, I'll turn it over to Bruce.