Though headcount grew considerably during the quarter, with an all-time recruiting high of 68 new employees, we did not reach the even more aggressive headcount growth built into guidance, and this contributed to our earnings upside. We continue to recruit and have aggressive hiring plans across the company.
A primary driver to our overall financial outperformance in the fourth quarter was our services revenue which at $30.8 million was up 60% from a year ago, considerably ahead of plan and reflecting unexpectedly strong growth in the number and scale of our implementation. As we shared in our last two calls, utilization rates are above our long-term target, particularly as our systems integrator partners ramp up their knowledge and credentials in the policy and suite domains as they did with ClaimCenter over the last several years. In the meanwhile, it is important to understand that our professionals services form the foundation for our lifelong, highly referenceable customer relationships, which drives market share gains and which we believe will impose a formidable barrier to entry for new entrants.
Our services are also profitable and provide positive cash flow, and the demand for Guidewire services reflects our current momentum in replacing legacy policy systems, the largest segment of the multibillion-dollar market for insurance core systems software. Our experience suggests that the complexity and criticality of policy replacement leads to this segment being several years behind claims, but upwards of 50% to 75% more valuable per unit premium. So we are very encouraged by the strong demand we are experiencing as exemplified by several strategic sales in the fourth quarter that I'd like to highlight.