Women filled 19.4 per cent of the seats on corporate boards of directors across public, government and private organizations, while more than half of all boards were composed entirely of men, according to a new study by Statistics Canada.

Using 2016 data collected from more than 12,700 corporations, the agency found that 28 per cent of the boards had just one woman and 15.2 per cent had more than one woman, but 56.8 per cent of the boards had no women at all.

While the share of women on boards of publicly-traded corporations has been well documented, this report provided the first comprehensive look across all types of companies including estimates for private corporations and government business enterprises as well, Statistics Canada said in the report published Tuesday.

The overall picture is "dismaying," said Tanya van Biesen, executive director for Catalyst Canada, whose mission is advancing women's progress in the workplace. The gap between women's educational and career achievements over the years and their representation in Canada's corporate boards is wide, she added.

"When you consider that for 20-plus years in this country, 57, 58 per cent of university graduates have been women, it is shocking... Can't we do better?"  van Biesen said.

Reports using more recent data, however, shows that the proportion of women on boards is improving, albeit slowly, she added.

In 2015, the country's largest securities regulator implemented a so-called comply-or-explain rule which requires most companies listed on the Toronto Stock Exchange to disclose each year how many women are on their board and in executive officer positions, among other things.

Since then, the proportion of women on publicly listed company boards has grown.

The latest Canadian Securities Administrators' report based on those disclosures from nearly 650 publicly traded companies showed that 15 per cent of board seats were held by women, but 66 per cent of issuers had at least one woman on their board.

That marked an improvement from four years earlier, when 11 per cent of the board seats were held by women and 49 per cent of these boards had at least one woman.

Statistics Canada's study published Tuesday shed light on the boards of government and private corporations -- the latter of which had the lowest proportion of women directors.

Government business enterprises had the highest share of women on corporate boards at 28.8 per cent, followed by public corporations at 20.5 per cent, while private corporations had just 17.4 per cent.

The agency's report was based on 2016 data collected through the Corporations Returns Act from 12,762 corporations, among which 44,658 directors were identified as members of a board.

"Women were more likely to be represented on corporate boards in service industries such as finance, management of companies and enterprises," researchers said.

Female directors were most prevalent on boards in the finance sector at 22.5 per cent, followed by utilities at 21.4 per cent, and management of companies and enterprises at 20.1 per cent. The construction sector and manufacturing had the lowest shares, at 12.8 per cent and 14.4 per cent, respectively.

Van Biesen notes that the sectors with larger proportion of women on their boards tend to be federally regulated, and subject to the Employment Equity Act for many years.

"In many of these industries that are not- or lesser-regulated, you're seeing the fact that without a need to report out, they have been able to lie below the radar and have not seen this as much of an imperative," she said.

However, she notes that Catalyst has seen "some shoots of hope" with growing interest from these sectors such as construction, manufacturing and energy to advance gender diversity.

Meanwhile, the proportion of women on boards also depended on where the controlling entity of the company was located.

Canadian-controlled entities had the highest share of women on boards at 21.3 per cent, followed by those controlled by entities in France -- where companies are subject to gender quotas for boards -- at 17.5 per cent, the study showed.

"Generally, these patterns seem to be consistent with the representation of women on corporate boards in these countries, reflecting the relatively higher representation in France and lower representation in Japan," Statistics Canada said.