Last weekend was the five-year anniversary of the collapse of Lehman Brothers, an event that kicked off the sinking of the world economy into recession and to the brink of worldwide depression. For the past week, media commentators have been remembering the harried months that followed, which seemed like the end of days at the time. (One good example is Neil Irwin’s walk down memory lane for the Washington Post.) But now, for many, the memory of those days has at least begun to fade, fear having been displaced by caution, which in turn is being displaced by cautious optimism—and even full-fledged optimism in some markets.

More proof of this cautious optimism can be found in August’s Architecture Billing Index, released today by the American Institute of Architects. With a national billings score of 53.8, up from July’s 52.7, it shows that architecture billings continue to grow at a steady rate, albeit sometimes ever-so-slightly shakily, as they have for nearly three years now.

It doesn’t seem so long ago since the bottom fell out. In January 2009, the index hit a nadir of 34.4, signaling massive contraction in the demand for architectural design services. Even the project inquiries index dipped below 50 for seven months (in March and May 2008, and from September 2008 to January 2009), which is something that had only been seen once before that point (in September 2001) and which we haven’t seen since. The next year and a half after the January 2009 lowpoint were followed by a steady, nerve-wracking slowing of the market’s rate of contraction. Then, we saw the first shaky and unpredictable green shoots, which began to appear at the end of 2010.

That feeling of uncertain, feeble, and precarious growth became so pervasive, however, that the renewed stability of the billings results for architecture has practically gone unnoticed. But growth has once again become the norm, not the exception. National billings have now grown for more than a year, except for one slip in April 2013 to 48.6. The inquiries index hasn’t experienced contraction since the dark days when we turned the calendar to 2009. Three of the nation’s regions have shown growth for more than a year now. (The only one that hasn’t, the Midwest, has been only slightly shakier, with eight of the past 12 months coming in above 50.) And three of the industry’s four sectors have shown growth for at least the past year. (The only one of those that hasn’t, the Commercial/Industrial sector, has shown growth for the past 11 months.)

Over the past few months, when I have seen the news from the AIA that the Architecture Billings Index has come in above 50, showing growth in the industry for design and architectural services, I have been pleasantly surprised. But that feeling is mistaken: I shouldn’t be surprised at all. While the economy might not be going gangbusters, growth is the norm again. That cautious, nervous optimism is a relic that the economy is slowly growing out of, and we all should too.

National Highlights
Billings: At 53.8, up from July’s national billings score of 52.7, this was the fourth straight month over 50. Twelve of the past 13 months, and seven of the eight months of 2013, have now been over 50.
Project Inquiries: At 63.0, down from July’s 66.4, this is the third straight month that inquiries have been above 60. Six of the eight months of 2013 have now come in above 60.

Regional Highlights
Northeast: At 54.4, up from 53.2, August was the 12th straight month above 50.
Midwest: At 52.8, up from 51.3, this was only the second straight month for the Midwest above 50, although eight of the past 11 months and five of the eight months of 2013 have all been over 50.
South: At 51.9, down from 54.0, this was the 14th straight month over 50.
West: At 54.8, up from 52.8, this was the 13th straight month over 50.

Sector Highlights
Multifamily Residential: At 52.1, down from 52.7, this was the 16th straight month above 50. August also represents 30 of the last 36 months above 50, solidifying the Multifamily Residential market’s status as one of the strongest sectors of the design and construction economy since the recovery from the financial crisis.
Commercial/Industrial: At 54.8, down from 55.8, this was the 11th straight month over 50.
Institutional: At 50.8, up from 50.5, this is the 13th straight month above 50.
Mixed Practice: At an astounding 60.1, up from 57.1, this is the 12th straight month above 50.