This year's survey of exhibition attendance – the 10th by The Art Newspaper – is as usual a compelling snapshot of curators' exhibition choices an public verdicts on those choices from around the world. The response to its annual arrival in polite art museum circules is generally: "Fascinating, yes. But frivolous and...well...potentially dangerous." The fear is that the ratings game, already an insidious driver of directorial decision-making, is given even greater prominence and calibration by the stark presentation of league tables. Nuanced and lofty ambitions for scholarship, stewardship and meaningful public engagement are pushed aside by a crude headcount, and the sheer volume of visitors enjoyed by the top 10 or 20 institutions become a stick with which to beat the 99.9% of musuems that are, and always will be, "also-rans" in the blockbuster race.

If one takes a look at the top 10 exhibitions in terms of daily attendance for each of, say, the past eight years (1998-2005), 80 in total, there are in fact relatively few surprises.

• 70% are monographic exhibitions of the work of famous men and one famous woman this year – a first – Coco Chanel.
• Over 75% are predominantly exhibitions of paintings, more than 50% are purely painting shows; then 6% are fashion and textiles exhibitions; 3% photography shows; 2.5% each for drawing and sculpture.
• 26% are of Impressionist, post-Impressionist or other 19th century work; 22% are Old Masters; 20% contemporary; 18% modern; and 12% antiquities.
• A small number of institutions dominate the list: the Metropolitan Museum of Art in New York had 14 shows in the top 10 in the past eight years; the Museum of Modern Art, New York, nine; the National Museum of Western Art, Tokyo, seven; Guggenheim(s), New York and Bilbao, seven; the National Gallery, Washington, four; the Philadelphia Museum of Art, three; and the Prado, Madrid, three exhibitions.
• The spread by country: the United States a whopping 43 (more than 50%); then Japan, seven; France, seven; Spain, five; Italy and the United Kingdom, four each; Russia and The Netherlands, three each; and Canada, Belgium, Germany and Greece, one each.
• The average total attendance was 445,000, ranging from the New York Museum of Modern Art's collection exiled in Berlin in 2004 with 1.2 million to "Warhol" at the Tate in 2002 at 218,000.
• The average daily attendance ranges from last year's most highly attended show "Hokusai" at the Tokyo National Museum, which attracted 9,500 a day, to a more modest 3,000 a day for Magritte at the Musees Royaux des Beaux Arts in Brussels in 1999.
• 13% of the exhibitions were about Van Gogh – two in this year's top 10: "Vincent van Gogh: The Drawings" at the Metropolitan Museum of Art, New York, and "Van Gogh in Context" at the Tokyo National Museum.

Trends over time are more difficult to detect. The average number of visitors in the top 10 most popular exhibitions varies between 420,000 (1999) and 540,000 (2004). The 2005 average total is down slightly at 493,000, but follows 2004's peak. This year's top 10 is led in total visitation – by some way – by the commercially conceived and executed "Tutankhamun and the Golden Age of the Pharaohs" in Los Angeles and Bonn. But there have only been four Egyptian shows in the past eight years. Above all, a handful of high profile, well resourced institutions appear to have a lock on the blockbuster market, and it is perhaps difficult to see what lessons there are for the rest of the sector – it is not simply about the levels of investment required, or about the access to loans. You also need to be located in or near a global tourist destination with its supportive demographics – New York, Tokyo, Paris, Washington.

Beyond these figures lie the challenges of accurately and timely data-collection, and as many questions posed as answered. The annual analysis shows the correlation between subject matter, institution, country and attendance. It would be interesting to be able to explore the correlation between some other variables, such as that between marketing budget and attendance, or between local and tourist visitors, were it possible to coax the figures out of museums. It probably isn't – at least in a form that allows meaningful comparison.

But given the role that attendance league tables play in the standing and branding of museums in the eyes of stakeholders – boards, donors, sponsors, government and indeed the wider public – perhaps there is some other data that could begin to fill the picture out, and provide a more rounded account of institutional vitality. These might include some simple indicators for acquisitions (perhaps insurance values); conservation (objects receiving attention); scholarly publications; educational outreach (tough to put a single figure on but not impossible); total visits (that is, including the permanent collection).

This is not a point about shortcomings in The Art Newspaper's annual stat-fest. Rather it is a point about the museum community internationally, and the challenges it faces in demonstrating its worth in an increasingly sceptical and numbers-driven climate. Expanding the basic common sectoral database is a logical step that would help to provide the evidential base from which to assert legitimate claims to public value. Musuems are entering a period in which public scepticism about their values and declared intentions is increasing considerably. The relatively modest effort required to collect and disseminate accurate and comparable basic data about more profound achievements than the headcount would be a smart investment. You can't beat something with nothing.