That's according to a third quarter survey of advertising agencies conducted by STRATA, which found 53% of agencies in their poll see their business increasing over last year. Client budgets in 2015 are expected to increase at 17% of agencies, while 57% of agencies polled see client budgets remaining flat compared to last year. 40% of agencies plan on hiring additional staff in the second half of this year, the highest percentage recorded in the STRATA Survey in five years. Attracting new clients is the top challenge for 33% of agencies, overtaking media mix (22%), which was the top agency challenge for three of the last four quarters.