Huguenot demographics are difficult to be precise about, and also substantially depend on the period you have in mind, although from your talk of 'exodus', I assume you refer to the late seventeenth through to the eighteenth century after the Revocation of the Edict of Nantes (1685, in case any lay reader is wondering). I'm not exceedingly familiar with Huguenot scholarship, but as no one else has yet replied, I'll supply you with some brief thoughts, starting off with some general observations that others might be able to add to in greater depth (and in a more direct answer to your question).

Demographics are a little complicated (the best extensive study on this that I know of — within my limited knowledge of the relevant literature, needless to add— is Philip Benedict's "The Huguenot Population of France, 1600-1685: The Demographic Fate and Customs of a Religious Minority" (Transactions of the American Philosophical Society 81, no. 5 (1991): i-ix, 1-164). In terms of population prior to the eighteenth century, see Benedict for more detail on almost every locality in France than you'll really ever need on this 'declining minority' (esp. Section A), as well as a shorter, general discussion on contemporary estimations of their population in the seventeenth century in Geoffrey Treasure's The Huguenots (Yale UP: 2013, pp. 283-85): the latter leaves the final word to Benedict's figure of 730,000 in the 1680s, which at any rate demonstrate a decline throughout the century, whether from emigration or disease, given their relatively more urban demographic, etc. Statistics are always contentious: Scoville's earlier work claimed (rather too high) that though it peaked around 1665, "a conservative estimate of their number in 1680-85 would doubtless fall between 1,500,000 and 2,000,000" (Warren Scoville, "The Huguenots in the French Economy, 1650-1750", The Quarterly Journal of Economics 67, no. 3 (1953): 423-444) — but either way, this would still lie at roughly 10% of the population. For Paris, the figure lay at about 8000-10,000 or 2% of the city's population, dropping to around 4000 by 1687 (see David Garrioch, The Huguenots of Paris and the Coming of Religious Freedom, 1685-1789, Cambridge UP: 2014, pp. 4 & 75, which is wonderful on the eighteenth century). More generally in regards to their backgrounds, Scoville (1953) describes, prior to the Revocation, that Protestantism:

... had appealed to Frenchmen in all social and economic classes — the intellectual and professional ranks, the peasantry, the artisan and commercial groups in cities, and the nobility. And there had been no indication whether one group or another would finally dominate the movement. During the latter half of the sixteenth century and until 1629 the nobility exerted a strong influence. At one time or another from a third to a half of the nobles turned from Catholicism to Protestantism [...] With the end of the Religious Wars in 1598 and after the fall of La Rochelle and the promulgation of the Edict of Alais in 1629, the most powerful noblemen abjured their new faith and re-entered the Catholic Church; the lesser nobility remained Protestant but sank into political oblivion. During the persecution immediately preceding and following the revocation, most of the latter group also abjured [...] the French nobility ceased to dominate the Protestant movement after 1629 and had little at all to do with it after 1685. — pp. 424-25

Still, I think its typically urban influence meant it was often the educated who floated towards Reformed thought, at least as the Catholic authorities themselves perceived it: "lawyers, bourgeois, merchants, young men with a taste for literature and freedom" and "spirited … artisans", in the words of the governor of Narbonne in the sixteenth century (Treasure, p. 115). The links between their overall educated backgrounds and economic benefit are to some extent also well highlighted by their very expulsion. Recent economic work, for example, demonstrates "substantial long-term effects of Huguenot settlement on the productivity of textile manufactories" in Prussia after 1685 (see Erik Hornung, "Immigration and the Diffusion of Technology: The Huguenot Diaspora in Prussia", American Economic Review 104, no. 1 (2014): 84-122); and of course there would be numerous other examples, such as in colonial America and the Netherlands (more generally, see the slightly dated Warren Scoville, "The Huguenots and the Diffusion of Technology", The Journal of Political Economy LX (1952): 294-311, 392-411). Even today, Fontainebleau (which annulled Nantes) is still regarded as a calamitous edict — in William Doyle’s phrasing, “the most disastrous single decision of [Louis XIV’s] reign” (Doyle, Old Regime France, 1648-1788, Oxford UP: 2001, p. 180) — since "140,000–160,000 religious refugees left the kingdom between 1685 and 1690”, an “exodus [which] signalled a decade of economic disruption".

Whatever the case, conversely, I think we mustn't exaggerate the economic impact of intolerance, to the point that Saint-Simon’s famous later criticism of the Revocation of the Edict of Nantes asserted. Scoville's (1953) article particularly went against prior paradigms that "usually represented [1685] as an important factor in the prolonged period of economic deterioration", which he mitigates: around 90% did not in fact emigrate, remaining as 'nouveaux convertis', most because they simply could not afford to. And while they evidently made contributions elsewhere, Scoville argues this wasn’t enough to substantially set back French competitiveness in trade — not, of course, that some industries like paper manufacturing weren’t nonetheless adversely affected, since they undeniably were. Naturally, one could also point out that those who were wealthy enough to leave had ample intellectual capital, without which the French economy suffered, such as goldsmiths, for example. Only, as Scoville suggests, other factors, including warfare, must be considered in contributing to France’s economic depression at the turn of the eighteenth century.